U.S. patent application number 11/833262 was filed with the patent office on 2007-11-22 for photonic integrated circuit device and elements thereof.
Invention is credited to Doron HANDELMAN.
Application Number | 20070269214 11/833262 |
Document ID | / |
Family ID | 36683972 |
Filed Date | 2007-11-22 |
United States Patent
Application |
20070269214 |
Kind Code |
A1 |
HANDELMAN; Doron |
November 22, 2007 |
PHOTONIC INTEGRATED CIRCUIT DEVICE AND ELEMENTS THEREOF
Abstract
A photonic integrated circuit (PIC) device is described. The PIC
device includes a set of optical transceivers including optical
transmitters and optical receivers, and an embedded optical
interconnect mesh operatively associated with the set of optical
transceivers and structured to enable at least one of the following
network architectures: a star network architecture, a bus/broadcast
network architecture, and a ring network architecture. Related
apparatus and methods are also described.
Inventors: |
HANDELMAN; Doron;
(Givatayim, IL) |
Correspondence
Address: |
DORON HANDELMAN
14 HAMA'AVAK STREET
GIVATAYIM
53520
IL
|
Family ID: |
36683972 |
Appl. No.: |
11/833262 |
Filed: |
August 3, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11035732 |
Jan 18, 2005 |
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11833262 |
Aug 3, 2007 |
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Current U.S.
Class: |
398/83 |
Current CPC
Class: |
G02B 6/43 20130101; G02B
6/4246 20130101 |
Class at
Publication: |
398/083 |
International
Class: |
H04J 14/00 20060101
H04J014/00 |
Claims
1. An indication method usable with a tunable laser module, the
method comprising: storing an indication that the tunable laser
module is assigned to provide at least one of communication
protection and communication restoration.
2. The method according to claim 1 and wherein the indication
comprises an identification of at least one of the following: at
least a portion of a separate optical transmitter; and at least a
portion of an optical communication system.
3. The method according to claim 1 and also comprising: providing
the at least one of communication protection and communication
restoration for at least one of the following: at least a portion
of a separate optical transmitter; and at least a portion of an
optical communication system.
4. The method according to claim 3 and wherein the indication
comprises an identification of at least one of the following: the
at least a portion of the separate optical transmitter; and the at
least a portion of the optical communication system.
5. The method according to claim 1 and also comprising: storing an
identification of at least one channel wavelength over which the at
least one of communication protection and communication restoration
is provided.
6. An identification method usable with a tunable laser module
which is capable of selectively transmitting in any one of a
plurality of channel wavelengths within at least one wavelength
band, the method comprising: storing an identification of at least
one channel wavelength of the plurality of channel wavelengths
which is unusable by the tunable laser module.
7. The method according to claim 6 and wherein the at least one
unusable channel wavelength comprises at least one channel
wavelength which is temporarily unusable.
8. The method according to claim 6 and also comprising: employing
said identification for avoiding an attempt to use said at least
one channel wavelength which is unusable by the tunable laser
module.
9. A method for enabling return to a state in a tunable laser
module, the method comprising: storing at least one bit enabling
return from a current channel grid configuration of the tunable
laser module to at least one of the following: a previous channel
grid configuration; and a default channel grid configuration.
10. The method according to claim 9 and wherein the default channel
grid configuration is preset.
11. The method according to claim 9 and wherein the default channel
grid configuration is user-selected.
12. The method according to claim 9 and also comprising: returning
from the current channel grid configuration in response to a
return-to-grid (RTG) instruction.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a division of U.S. patent
application Ser. No. 11/035,732, filed Jan. 18, 2005.
FIELD OF THE INVENTION
[0002] The present invention generally relates to photonic
integrated circuit (PIC) devices with optical interconnects and to
elements thereof.
BACKGROUND OF THE INVENTION
[0003] Increase of communication capacity within chips, boards,
modules, and subsystems of chips is limited today due to the
electrical interconnects that are used in the chips, boards,
modules, and subsystems of chips. Optical interconnects are
considered as enabling better performance than electrical
interconnects, for example in terms of bandwidth and susceptibility
to electromagnetic noise, and therefore photonic integrated circuit
(PIC) devices that use optical interconnects have been
developed.
[0004] PIC devices and optical interconnects for optical backplanes
and chip-to-chip communication are described in the following
publications:
[0005] Published US Patent application US2004/0067006 A1 of Welch
et al, which describes transmitter photonic integrated circuit
(TXPIC) chips;
[0006] an article entitled "Linking with Light", by Neil Savage, in
IEEE Spectrum, August 2002, pages 32-36;
[0007] an article entitled "Self-Organized Lightwave Network Based
on Waveguide Films for Three-Dimensional Optical Wiring Within
Boxes", by Yoshimura et al in Journal of Lightwave Technology, Vol.
22, No. 9, September 2004, pages 2091-2099;
[0008] an article entitled "Board-Level Optical Interconnection and
Signal Distribution Using Embedded Thin-Film Optoelectronic
Devices", by Cho et al in Journal of Lightwave Technology, Vol. 22,
No. 9, September 2004, pages 2111-2118;
[0009] an article entitled "Optical Backplane System Using
Waveguide-Embedded PCBs and Optical Slots", by Yoon et al in
Journal of Lightwave Technology, Vol. 22, No. 9, September 2004,
pages 211-2127;
[0010] an article entitled "PCB-Compatible Optical Interconnection
Using 45.degree.-Ended Connection Rods and Via-Holed Waveguides",
by Rho et al in Journal of Lightwave Technology, Vol. 22, No. 9,
September 2004, pages 2128-2134; and
[0011] an article entitled "Board-to-Board Optical Interconnection
System Using Optical Slots", by Cho et al in IEEE Photonics
Technology Letters, Vol. 16, No. 7, July 2004, pages 1754-1756.
[0012] Further aspects of technologies and related art that may be
useful in understanding the present invention are described in the
following publications:
[0013] Implementation Agreement OIF-TL-01.1 entitled "Tunable Laser
Implementation Agreement", Selvik et al, of the Physical and Link
Layer (PLL) Working Group of the Optical Internetworking Forum
(OIF), dated 27 Nov. 2002 at the web site
www.oiforum.com/public/impagreements.html;
[0014] Implementation Agreement OIF-TLMSA-01.1 entitled
"Multi-Source Agreement for CW Tunable Lasers", Jeff Hutchins et
al, of the Physical and Link Layer (PLL) Working Group of the
Optical Internetworking Forum (OIF), dated 30 May 2003 at the web
site www.oiforum.com/public/impagreements.html;
[0015] Implementation Agreement OIF-ITLA-MSA-01.1 entitled
"Integratable Tunable Laser Assembly Multi Source Agreement", Jeff
Hutchins et al, Optical Internetworking Forum (OIF), dated 15 Jun.
2004 at the web site www.oiforum.com/public/impagreements.html;
[0016] An OIF document entitled "OIF Tunable Laser Projects", by
Jeff Hutchins at the web site
www.oiforum.com/public/whitepapers.html;
[0017] an article entitled "Standardizing Tunable Lasers", by Jeff
Hutchins in Photonics Spectra, June 2004, pages 88-92;
[0018] an article entitled "Surface-Emitting Laser--Its Birth and
Generation of New Optoelectronics Field", by Kenichi Iga, in IEEE
Journal on Selected Topics in Quantum Electronics, Vol. 6, No. 6,
November/December 2000, pages 1201-1215;
[0019] an article entitled "VCSELs turn to high-speed
transmission", by Jeff Hecht in Laser Focus World, February 2001,
pages 123-130;
[0020] an article entitled "Packet switching takes steps toward
optical", by Jeff Hecht in Laser Focus World, June 2002, pages
131-139;
[0021] an article entitled "Optical Signal Processing for Optical
Packet Switching Networks", by Blumenthal et al in IEEE Optical
Communications, February 2003, pages S23-S29;
[0022] an article entitled "Restoration schemes for agile photonic
networks", by Peter Roorda et al in Lightwave Europe, August 2003,
pages 10-12;
[0023] an article entitled "Photonic Crystals Show Promise for
Wiring Optical Chips", by Dr. Dominic F. G. Gallagher in
EuroPhotonics, February/March 2004, pages 20-21;
[0024] an article entitled "A Novel Polarization Splitter Based on
the Photonic Crystal Fiber With Nonidentical Dual Cores", by Zhang
et al in IEEE Photonics Technology Letters, Vol. 16, No. 7, July
2004, pages 1670-1672;
[0025] an article entitled "Photonic Crystals: A Growth Industry",
by Daniel C. McCarthy in Photonics Spectra, June 2002, pages
54-60;
[0026] an article entitled "IETF Work on Protection and Restoration
for Optical Networks", by David W. Griffith in Optical Networks
Magazine, July/August 2003, pages 101-106;
[0027] an article entitled "All-Optical Switching Technologies for
Protection Applications", by Appelman et al in IEEE Optical
Communications, November 2004, pages S35-S40;
[0028] Chapter 6 on pages 57-72 in The Fiber Optic LAN Handbook,
Fifth Edition, Codenol.RTM. Technology Corporation, 1993;
[0029] The following chapters in The Communications Handbook, CRC
Press & IEEE Press, 1997, Editor-in-Chief Jerry D. Gibson:
Chapter 57 on pages 774-788; Chapter 60 on pages 824-831; and
Chapter 64 on pages 872-882;
[0030] U.S. patent application Ser. No. 10/619,413 of Handelman,
filed 16 Jul. 2003, now U.S. Pat. No. 7,167,620, which describes
devices and methods for all-optical processing and storage;
[0031] The following published US Patent Applications: US
2003/0048506 A1; US 2003/0043430 A1; US 2002/0048067 A1; US
2004/0184714 A1; and US 2004/0208418 A1; and
[0032] The following U.S. Pat. Nos. 6,404,522; 6,574,018;
6,738,581; and 6,763,191.
[0033] The disclosures of all references mentioned above and
throughout the present specification, as well as the disclosures of
all references mentioned in those references, are hereby
incorporated herein by reference.
SUMMARY OF THE INVENTION
[0034] The present invention, in preferred embodiments thereof,
seeks to provide photonic integrated circuit (PIC) devices with
improved functionality, structure and capabilities, particularly,
but not only, with respect to architecture of the PIC devices,
configurability of the PIC devices, communication between optical
transceivers comprised in or associated with the PIC devices,
protection and restoration of communication between optical
transceivers comprised in or associated with the PIC devices, and
operability of the PIC devices and of optical transceivers
comprised in or associated with the PIC devices.
[0035] The term "optical transceiver" is used throughout the
present specification and claims to include a combination of an
optical transmitter and an optical receiver.
[0036] The term "optical transmitter" is used throughout the
present specification and claims to include a light emitting
element that is capable of transmitting optical signals and at
least part of an electronic circuit that modulates, drives and
controls the light emitting element. The light emitting element is
modulated either by direct modulation or by external modulation and
the at least part of the electronic circuit includes a respective
modulation circuit. In a case where the light emitting element is
modulated by external modulation, the optical transmitter also
includes an external modulator. Examples, which are not meant to be
limiting, of light emitting elements of appropriate optical
transmitters include the following: a laser; and a light-emitting
diode (LED).
[0037] The term "optical receiver" is used throughout the present
specification and claims to include a light sensitive element that
is capable of receiving optical signals and at least part of an
electronic circuit that converts received optical signals into
electronic signals and controls the light sensitive element.
Examples, which are not meant to be limiting, of light sensitive
elements of appropriate optical receivers include the following: a
photodiode (PD); and a photo-detector.
[0038] Further objects and features of the present invention will
become apparent to those skilled in the art from the following
description and the accompanying drawings.
[0039] There is thus provided in accordance with a preferred
embodiment of the present invention a photonic integrated circuit
(PIC) device including a set of optical transceivers including
optical transmitters and optical receivers, and an embedded optical
interconnect mesh operatively associated with the set of optical
transceivers and structured to enable at least one of the following
network architectures: a star network architecture, a bus/broadcast
network architecture, and a ring network architecture.
[0040] Additionally, the PIC device also includes an interface unit
associating the set of optical transceivers with at least one of
the following: subsystems of an electronic chip which communicate
with each other via the set of optical transceivers, and a set of
electronic chips which communicate with each other via the set of
optical transceivers.
[0041] Further additionally, the PIC device also includes a link
adder operative to associate an external optical unit with the
embedded optical interconnect mesh so as to enable the external
optical unit to function in the network architecture enabled by the
embedded optical interconnect mesh. The external optical unit
preferably includes at least one of the following: an external
optical transceiver, an external optical network, an external
optical switch, an external optical router, an external optical
linecard, an external PIC device, an external optical processing
element, an external optical decoder, and a PIC monitoring
system.
[0042] Preferably, the embedded optical interconnect mesh includes
at least one of the following: a free-space optical interconnect
mesh, a waveguide optical interconnect mesh, a fiber interconnect
mesh, a photonic crystal waveguide optical interconnect mesh, and a
combination of at least two of the following: a free-space optical
interconnect mesh, a waveguide optical interconnect mesh, a fiber
interconnect mesh, and a photonic crystal waveguide optical
interconnect mesh. The waveguide optical interconnect mesh
preferably includes at least one polymeric optical waveguide.
[0043] Preferably, each optical transmitter in the set of optical
transceivers includes at least one of the following: a
multi-channel laser array, a light emitting diode (LED), a tunable
laser, a fixed-channel laser, and a tunable multi-channel laser
array. Each optical receiver in the set of optical transceivers
preferably includes at least one of the following: a photodiode
(PD), and a photo-detector. The photodiode preferably includes at
least one of the following: a p-i-n photodiode, and an avalanche
photodiode (APD). The photo-detector preferably includes a
metal-semiconductor-metal (MSM) photo-detector.
[0044] Additionally, the PIC device also includes stacked layers
which include the following: at least a portion of optical
transceivers in the set of optical transceivers, and at least a
portion of the embedded optical interconnect mesh.
[0045] Preferably, the set of optical transceivers includes at
least one optical transceiver which is used for providing at least
one of communication protection and communication restoration. At
least one optical transceiver in the set of optical transceivers
which is not used for providing at least one of communication
protection and communication restoration and the at least one
optical transceiver which is used for providing at least one of
communication protection and communication restoration are
preferably at least partially included in at least one of the
following: separate layers of the PIC device, and separate areas of
the PIC device.
[0046] Preferably, the embedded optical interconnect mesh includes
a reflecting optical element, and a bidirectional coupler
including: a plurality of ports on a first side which are coupled
to the set of optical transceivers, and at least one port on a
second side which is coupled to the reflecting optical element,
wherein light transmitted by an optical transmitter in the set of
optical transceivers via a port on the first side is reflected by
the reflecting optical element and distributed among the optical
receivers in the set of optical transceivers via the at least one
port on the second side which is coupled to the reflecting optical
element, and via ports on the first side that are associated with
the optical receivers. The bi-directional coupler preferably
includes a star coupler (SC).
[0047] The PIC device also preferably includes isolators
operatively associated with the optical transmitters in the set of
optical transceivers and operative to protect the optical
transmitters from back reflections from the reflecting optical
element.
[0048] The PIC device may preferably be included in a photonic
switch.
[0049] There is also provided in accordance with a preferred
embodiment of the present invention an optical interconnect
including a plurality of optical paths, a reflecting optical
element, and a bidirectional coupler including: a plurality of
ports on a first side which are coupled to the plurality of optical
paths, and at least one port on a second side which is coupled to
the reflecting optical element, wherein light transmitted via an
optical path of the plurality of optical paths and a port on the
first side is reflected by the reflecting optical element and
distributed among the plurality of optical paths via the at least
one port on the second side which is coupled to the reflecting
optical element, and via ports on the first side that are coupled
to the plurality of optical paths.
[0050] Also in accordance with a preferred embodiment of the
present invention there is provided a tunable laser module
including a light emitter, and a register storing an indication
that the tunable laser module is assigned to provide at least one
of communication protection and communication restoration for at
least one of the following: at least a portion of a separate
optical transmitter, and at least a portion of an optical
communication system.
[0051] Preferably, the indication includes an identification of at
least one of the following: the at least a portion of the separate
optical transmitter, and the at least a portion of the optical
communication system.
[0052] Further preferably, the register stores an identification of
at least one channel wavelength over which the at least one of
communication protection and communication restoration is
provided.
[0053] Preferably, the separate optical transmitter includes at
least one of the following: a VCSEL, a LED, an EEL, a tunable
laser, a fixed-channel laser, and a tunable VCSEL.
[0054] Further in accordance with a preferred embodiment of the
present invention there is provided a tunable laser module
including a circuit structure which is at least partially embedded
in a PIC device, the circuit structure including at least a portion
of the tunable laser module, and a register storing an indication
identifying a location within the PIC device in which the circuit
structure is located.
[0055] Preferably, the indication identifying the location within
the PIC device includes at least one of the following: an
indication of a layer of the PIC device in which the circuit
structure is included, and an indication of an area of the PIC
device in which the circuit structure is located.
[0056] Yet further in accordance with a preferred embodiment of the
present invention there is provided a PIC device including a first
optical transceiver, a second optical transceiver, and a register
storing an indication indicating that the first optical transceiver
is assigned to provide at least one of communication protection and
communication restoration for the second optical transceiver.
[0057] Still further in accordance with a preferred embodiment of
the present invention there is provided a multi-channel laser array
module including a light emitting array capable of simultaneously
transmitting in a plurality of channel wavelengths within at least
one wavelength band, and a register storing an identification of at
least one channel wavelength of the plurality of channel
wavelengths which is unusable by the multi-channel laser array
module. The at least one unusable channel wavelength may preferably
include at least one channel wavelength which is temporarily
unusable.
[0058] Preferably, the light emitting array includes at least one
of the following: a VCSEL array, a tunable VCSEL array, an EEL
array, an assembly combining a plurality of fixed-channel lasers,
and an assembly combining a plurality of tunable single-channel
lasers.
[0059] There is also provided in accordance with a preferred
embodiment of the present invention a tunable laser module
including a light emitter capable of selectively transmitting in
any one of a plurality of channel wavelengths within at least one
wavelength band, and a register storing an identification of at
least one channel wavelength of the plurality of channel
wavelengths which is unusable by the tunable laser module. The at
least one unusable channel wavelength may preferably include at
least one channel wavelength which is temporarily unusable.
[0060] Further in accordance with a preferred embodiment of the
present invention there is provided a tunable laser module
including a light emitter, and a register storing at least one bit
enabling return from a current channel grid configuration of the
tunable laser module to at least one of the following: a previous
channel grid configuration, and a default channel grid
configuration.
[0061] Also in accordance with a preferred embodiment of the
present invention there is provided a PIC device including a first
multi-channel laser array module capable of simultaneously
transmitting over a first set of channel wavelengths, a second
multi-channel laser array module capable of simultaneously
transmitting over a second set of channel wavelengths, where the
channel wavelengths of the second set are different from the
channel wavelengths of the first set, an optical receiver capable
of simultaneously receiving transmissions from the first
multi-channel laser array module over the first set of channel
wavelengths and from the second multi-channel laser array module
over the second set of channel wavelengths, and an embedded optical
interconnect mesh which optically interconnects the first
multi-channel laser array module and the second multi-channel laser
array module to the optical receiver.
[0062] Preferably, the second multi-channel laser array module, or
a portion thereof, provides at least one of communication
protection and communication restoration for the first
multi-channel laser array module.
[0063] Further in accordance with a preferred embodiment of the
present invention there is provided an optical interconnection
method for use with a PIC device, the method including embedding,
within the PIC device, an optical interconnect mesh structured to
enable at least one of the following network architectures: a star
network architecture, a bus/broadcast network architecture, and a
ring network architecture.
[0064] Additionally, the method also includes associating the
optical interconnect mesh with a set of optical transceivers.
[0065] Further additionally, the method also includes associating
the set of optical transceivers with at least one of the following:
subsystems of an electronic chip which communicate with each other
via the set of optical transceivers, and a set of electronic chips
which communicate with each other via the set of optical
transceivers.
[0066] Still further additionally, the method also includes
associating an external optical unit with the optical interconnect
mesh so as to enable the external optical unit to function in the
network architecture enabled by the optical interconnect mesh.
[0067] The method also preferably includes using at least one
optical transceiver from the set of optical transceivers for
providing at least one of communication protection and
communication restoration.
[0068] Additionally, the method also includes selecting at least
one channel wavelength usable by the at least one optical
transceiver for providing the at least one of communication
protection and communication restoration over the at least one
channel wavelength.
[0069] There is also provided in accordance with a preferred
embodiment of the present invention an optical interconnection
method for use with a PIC device, the method including embedding,
within the PIC device, an optical interconnect mesh structured to
enable a configurable network architecture, and enabling
reconfiguration from a first network architecture to a second
network architecture.
[0070] Preferably, each of the first network architecture and the
second network architecture includes one of the following network
architectures: a star network architecture, a bus/broadcast network
architecture, and a ring network architecture.
[0071] Also in accordance with a preferred embodiment of the
present invention there is provided an indication method usable
with a tunable laser module, the method including storing an
indication that the tunable laser module is assigned to provide at
least one of communication protection and communication
restoration.
[0072] Additionally, the method also includes providing the at
least one of communication protection and communication restoration
for at least one of the following: at least a portion of a separate
optical transmitter, and at least a portion of an optical
communication system.
[0073] Preferably, the indication includes an identification of at
least one of the following: the at least a portion of the separate
optical transmitter, and the at least a portion of the optical
communication system.
[0074] Additionally, the method also includes storing an
identification of at least one channel wavelength over which the at
least one of communication protection and communication restoration
is provided.
[0075] The storing preferably includes storing the indication in at
least one of the following: a register of the tunable laser module,
a register of the separate optical transmitter, and a control and
management system of the optical communication system.
Additionally, the storing includes storing an identification of a
channel wavelength over which the at least one of communication
protection and communication restoration is provided in at least
one of the following: a register of the tunable laser module, a
register of the separate optical transmitter, and a control and
management system of the optical communication system.
[0076] Further in accordance with a preferred embodiment of the
present invention there is provided an indication method usable
with an optical transmitter, the method including at least
partially embedding in a PIC device a circuit structure including
at least a portion of the optical transmitter, and storing an
indication identifying a location within the PIC device in which
the circuit structure is located. The optical transmitter
preferably includes at least one of the following: a tunable laser
module, and a multi-channel laser array module.
[0077] There is also provided in accordance with a preferred
embodiment of the present invention an identification method usable
with a tunable laser module which is capable of selectively
transmitting in any one of a plurality of channel wavelengths
within at least one wavelength band, the method including storing
an identification of at least one channel wavelength of the
plurality of channel wavelengths which is unusable by the tunable
laser module.
[0078] Further in accordance with a preferred embodiment of the
present invention there is provided a method for enabling return to
a state in a tunable laser module, the method including storing at
least one bit enabling return from a current channel grid
configuration of the tunable laser module to at least one of the
following: a previous channel grid configuration, and a default
channel grid configuration.
[0079] Yet further in accordance with a preferred embodiment of the
present invention there is provided an identification method usable
with a multi-channel laser array module which is capable of
simultaneously transmitting in a plurality of channel wavelengths
within at least one wavelength band, the method including storing
an identification of at least one channel wavelength of the
plurality of channel wavelengths which is unusable by the
multi-channel laser array module.
[0080] Still further in accordance with a preferred embodiment of
the present invention there is provided an indication method usable
with a multi-channel laser array module, the method including
storing an indication that at least one single-channel laser in the
multi-channel laser array module is assigned to provide at least
one of communication protection and communication restoration.
[0081] Additionally, the method also includes providing the at
least one of communication protection and communication restoration
for at least one of the following: at least a portion of a separate
optical transmitter, at least a portion of an optical communication
system, and a portion of the multi-channel laser array module that
does not include the at least one single-channel laser.
[0082] There is also provided in accordance with a preferred
embodiment of the present invention a method for verifying optical
functionality of an optical transmitter in a PIC device which
includes a plurality of optical transmitters and a plurality of
optical receivers, the method including transmitting from the
optical transmitter, via the PIC device, an optical signal which is
individually assigned to the optical transmitter, and determining
whether the individually assigned optical signal is correctly
received at at least one of the plurality of optical receivers.
[0083] Further in accordance with a preferred embodiment of the
present invention there is provided a method for providing at least
one of communication protection and communication restoration in a
PIC device, the method including embedding, within the PIC device,
an optical interconnect mesh structured to enable a network
architecture in which optical transceivers associated with the
optical interconnect mesh communicate with each other, determining
a first sub-group of the optical transceivers as a sub-group of
active optical transceivers for use in normal communication, and
assigning, in response to a determination of the first sub-group, a
second sub-group of the optical transceivers as a protecting
sub-group of optical transceivers for providing at least one of
communication protection and communication restoration for the
first sub-group.
[0084] Preferably, the assigning includes automatically assigning
the second sub-group of the optical transceivers as the protecting
sub-group of optical transceivers.
[0085] Additionally, the method also includes maintaining an
identification of the first sub-group and an identification of the
second sub-group at a control and management system.
[0086] Also in accordance with a preferred embodiment of the
present invention there is provided an optical receiving method for
use with a PIC device, the method including embedding in the PIC
device a first multi-channel laser array module capable of
simultaneously transmitting over a first set of channel
wavelengths, and a second multi-channel laser array module capable
of simultaneously transmitting over a second set of channel
wavelengths, where the channel wavelengths of the second set are
different from the channel wavelengths of the first set, and
simultaneously receiving at an optical receiver, via an optical
interconnect mesh in the PIC device which interconnects the optical
receiver to the first multi-channel laser array module and to the
second multi-channel laser array module, transmissions provided by
the first multi-channel laser array module over the first set of
channel wavelengths and transmissions provided by the second
multi-channel laser array module over the second set of channel
wavelengths.
[0087] There is also provided in accordance with a preferred
embodiment of the present invention an optical switching method
including determining, from a plurality of optical packets, a first
group of optical packets that can be switched by a flow-switching
technique (FST) and a second group of optical packets that cannot
be switched by FST, and switching the first group of optical
packets by using FST and the second group of optical packets by
using packet switching.
[0088] Preferably, the first group of optical packets includes at
least one of the following: at least one optical burst that exceeds
a packet-length threshold, and at least one optical packet that is
combinable with other optical packets.
BRIEF DESCRIPTION OF THE DRAWINGS
[0089] The present invention will be understood and appreciated
more fully from the following detailed description, taken in
conjunction with the drawings in which:
[0090] FIG. 1 is a simplified partly pictorial partly block diagram
illustration of a preferred implementation of a photonic integrated
circuit (PIC) device with an embedded optical interconnect mesh
structured to enable a configurable network architecture, the PIC
device being constructed and operative in accordance with a
preferred embodiment of the present invention;
[0091] FIG. 2 is a simplified block diagram illustration of a
preferred implementation of a tunable laser module constructed and
operative in accordance with a preferred embodiment of the present
invention;
[0092] FIG. 3 is a simplified block diagram illustration of a
preferred implementation of a multi-channel laser array module
constructed and operative in accordance with a preferred embodiment
of the present invention;
[0093] FIG. 4 is a simplified flowchart illustration of a preferred
method of operation of the PIC device of FIG. 1;
[0094] FIG. 5 is a simplified flowchart illustration of another
preferred method of operation of the PIC device of FIG. 1;
[0095] FIG. 6 is a simplified flowchart illustration of a preferred
method of operation of the tunable laser module of FIG. 2;
[0096] FIG. 7 is a simplified flowchart illustration of a preferred
method of operation of any of the tunable laser module of FIG. 2
and the multi-channel laser array module of FIG. 3;
[0097] FIG. 8 is a simplified flowchart illustration of another
preferred method of operation of the tunable laser module of FIG.
2;
[0098] FIG. 9 is a simplified flowchart illustration of yet another
preferred method of operation of the tunable laser module of FIG.
2;
[0099] FIG. 10 is a simplified flowchart illustration of a
preferred method of operation of the multi-channel laser array
module of FIG. 3;
[0100] FIG. 11 is a simplified flowchart illustration of another
preferred method of operation of the multi-channel laser array
module of FIG. 3;
[0101] FIG. 12 is a simplified flowchart illustration of a
preferred method of verifying optical functionality of an optical
transmitter in the PIC device of FIG. 1;
[0102] FIG. 13 is a simplified flowchart illustration of a
preferred method for providing at least one of communication
protection and communication restoration in the PIC device of FIG.
1;
[0103] FIG. 14 is a simplified flowchart illustration of a
preferred optical receiving method useful with the PIC device of
FIG. 1; and
[0104] FIG. 15 is a simplified flowchart illustration of a
preferred optical switching method useful with the PIC device of
FIG. 1.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
[0105] The present invention, in preferred embodiments thereof,
seeks to provide photonic integrated circuit (PIC) devices with
improved functionality, structure and capabilities, particularly,
but not only, with respect to architecture of the PIC devices,
configurability of the PIC devices, communication between optical
transceivers comprised in or associated with the PIC devices,
protection and restoration of communication between optical
transceivers comprised in or associated with the PIC devices, and
operability of the PIC devices and of optical transceivers
comprised in or associated with the PIC devices. Such PIC devices
may, for example, be useful as building blocks or entire systems in
various applications including, for example which is not meant to
be limiting, the following applications: optical switching and
routing applications; applications involving chip-to-chip
communication; applications involving linecard-to-linecard
communication and optical backplane applications; applications
involving interchip communication; optical processing applications;
optical decoding applications; and applications that use optical
links and optical communication.
[0106] The term "photonic integrated circuit device" is used
throughout the present specification and claims in a broad sense to
include an optoelectronic circuit comprising optical interconnects
and also comprising optoelectronic elements or portions thereof, or
a device including such an optoelectronic circuit. The photonic
integrated circuit device also includes or is associated with a
conventional large-scale integrated (LSI) electronic circuit or
conventional LSI components. The photonic integrated circuit device
is suitable for integration into a hybrid electrical-optical
printed circuit board (PCB) or is integrated into a hybrid
electrical-optical PCB. Each optical interconnect in the photonic
integrated circuit device includes at least one of the following: a
free-space optical interconnect; a waveguide optical interconnect;
a fiber interconnect; and an optical interconnect based on photonic
crystal waveguides.
[0107] A PIC device in accordance with a preferred embodiment of
the present invention includes a set of optical transceivers
comprising optical transmitters and optical receivers, and an
embedded optical interconnect mesh operatively associated with the
set of optical transceivers and structured to enable at least one
of the following network architectures: a star network
architecture; a bus/broadcast network architecture; and a ring
network architecture.
[0108] Reference is now made to FIG. 1, which is a simplified
partly pictorial partly block diagram illustration of a preferred
implementation of a PIC device 10 with an embedded optical
interconnect mesh 20 structured to enable a configurable network
architecture, the PIC device 10 being constructed and operative in
accordance with a preferred embodiment of the present invention.
Preferably, the configurable network architecture enables
reconfiguration from a first network architecture to a second
network architecture where each of the first network architecture
and the second network architecture preferably includes one of the
following network architectures: a star network architecture; a
bus/broadcast network architecture; and a ring network
architecture. The PIC device 10 is preferably operative in each of
the star network architecture, the bus/broadcast network
architecture, and the ring network architecture as described
below.
[0109] The PIC device 10 preferably includes a set of optical
transceivers 30 comprising a plurality of optical transmitters 40
and a plurality of optical receivers 50. The set of optical
transceivers 30 is preferably associated with the optical
interconnect mesh 20. By way of example, which is not meant to be
limiting, the plurality of optical transmitters 40 in FIG. 1
include vertical cavity surface-emitting lasers (VCSELs), or
multi-channel arrays thereof with combined optical outputs, and a
tunable single-channel or multi-channel optical transmitter 60
comprising a tunable VCSEL, and the plurality of optical receivers
50 include photodiodes (PDs), or arrays of PDs with combined
optical inputs. Each PD preferably includes at least one of the
following: a p-i-n photodiode; and an avalanche photodiode
(APD).
[0110] It is however appreciated that each of the plurality of
optical transmitters 40 may alternatively or additionally include
any other appropriate type of optical transmitter, such as a
single-channel or multi-channel array configuration of at least one
of the following types: a light emitting diode (LED); an
edge-emitting laser (EEL); a tunable laser; and a fixed-channel
laser. Each of the plurality of optical receivers 50 may
alternatively or additionally include any other appropriate type of
optical receiver, such as a photo-detector including, for example
which is not meant to be limiting, a metal-semiconductor-metal
(MSM) photo-detector.
[0111] The embedded optical interconnect mesh 20 preferably
includes a plurality of optical paths 65, a reflecting optical
element 70, and a bi-directional coupler 80. The optical paths 65
may be referred to as branches or segments of the optical
interconnect mesh 20.
[0112] The bi-directional coupler 80 preferably includes a star
coupler (SC) having a plurality of ports 90 on a first side and at
least one port 100 on a second side. The ports 90 are preferably
coupled to the set of optical transceivers 30 via the optical paths
65, and the at least one port 100 is preferably coupled to the
reflecting optical element 70 via an optical path 110. By way of
example, which is not meant to be limiting, the bi-directional
coupler 80 in FIG. 1 includes a single port 100.
[0113] The reflecting optical element 70 preferably includes a
mirror, such as a micro-mirror, which is preferably inserted in a
"via" hole (not shown) in the PIC device 10 so that a reflecting
facet of the micro-mirror is perpendicular to the optical path 110
thus reflecting light propagating via the optical path 110 towards
the micro-mirror back along the same path.
[0114] Preferably, the PIC device 10 also includes a plurality of
isolators 120 operatively associated with or comprised in the
optical transmitters 40 and 60. The isolators 120 are preferably
operative to protect the optical transmitters 40 and 60 from back
reflections of light from the reflecting optical element 70.
[0115] The embedded optical interconnect mesh 20 preferably
includes at least one of the following: a free-space optical
interconnect mesh; a waveguide optical interconnect mesh; a fiber
interconnect mesh; a photonic crystal waveguide optical
interconnect mesh; and a combination of at least two of the
following: a free-space optical interconnect mesh; a waveguide
optical interconnect mesh; a fiber interconnect mesh; and a
photonic crystal waveguide optical interconnect mesh. The waveguide
optical interconnect mesh preferably includes at least one
polymeric optical waveguide.
[0116] It is appreciated that at least a portion of the embedded
optical interconnect mesh 20 and at least a portion of optical
transceivers 30 in the set of optical transceivers 30 are
preferably comprised in stacked layers of the PIC device 10.
Additionally, the optical transceivers 30 in the set of optical
transceivers 30 may be spread throughout large portions of the PIC
device 10 and placed in various areas of the PIC device 10 and in
various orientations. Thus, the embedded optical interconnect mesh
20 may comprise complex structures of the optical paths 65 in two
or three dimensions with, for example, reflectors at corners of
some optical paths 65 for deflecting light, and intermediate
couplers among some of the optical transceivers 30 and the
bidirectional coupler 80.
[0117] By way of example, which is not meant to be limiting, in
FIG. 1 one optical transceiver 30 is shown to have a different
orientation than the other optical transceivers 30, and a mirror
122 is used to deflect light emanating from the optical transmitter
40 of the one optical transceiver 30 and another mirror 124 is used
to deflect light towards the optical receiver 50 of the one optical
transceiver 30. It is appreciated that additional mirrors may be
used, as necessary, in the PIC device 10 to direct transmitted
optical signals towards the reflecting optical element 70, and
optical signals reflected by the reflecting optical element 70
towards corresponding optical receivers 50.
[0118] Further by way of example, which is not meant to be
limiting, in FIG. 1 an intermediate coupler (ICPLR) 126 is used
between the bidirectional coupler 80 and two optical transmitters
40, and a single isolator 120, placed between the ICPLR 126 and the
bi-directional coupler 80, is used for protecting the two optical
transmitters 40 from back reflections of light from the reflecting
optical element 70. It is appreciated that use of the ICPLR 126
reduces the number of isolators 120 in the PIC device 10 and the
number of ports 90 used in the bidirectional coupler 80, and also
reduces received optical power of back reflections received at the
optical transmitters 40 due to distribution by the ICPLR 126. The
ICPLR 126 may, for example, include a star coupler having two input
ports (not shown) and one output port (not shown).
[0119] The PIC device 10 also preferably includes an interface unit
130. The interface unit 130 preferably associates the set of
optical transceivers 30 with at least one of the following:
subsystems of an electronic chip (not shown) which communicate with
each other via the set of optical transceivers 30; and a set of
electronic chips (not shown) which communicate with each other via
the set of optical transceivers 30. The subsystems of the
electronic chip and the set of electronic chips may be comprised in
the PIC device 10 or associated with the PIC device 10.
[0120] The interface unit 130 may, for example, be embedded in a
layer of the PIC device 10 which is under the optical transceivers
30. Alternatively, the interface unit 130 may be adjacent to the
optical transceivers 30. The interface unit 130 may, for example,
include LSI electronic circuit components (not shown) interfacing
the subsystems of the electronic chip and the electronic chips with
the optical transceivers 30. Additionally, the interface unit 130
includes at least part of an electronic circuit which modulates,
drives, and controls the optical transmitters 40 and 60, and at
least part of an electronic circuit that converts received optical
signals into electronic signals and controls the optical receivers
50. It is appreciated that the interface unit 130 may be comprised
of separate electronic sub-circuits.
[0121] Preferably, each optical transceiver 30, together with a
corresponding associated portion of the interface unit 130 and a
corresponding isolator 120, forms an opto-electronic (OE) node in
the network architecture of the PIC device 10. Each such portion of
the interface unit 130 which is associated with an optical
transceiver 30 preferably includes or is associated with a
processing element (not shown) capable of performing network
processing operations that are associated with a conventional
network, such as detection of an address of a node, re-transmission
of information received at the node, etc.
[0122] The PIC device 10 also preferably includes a link adder 140.
The link adder 140 is preferably operative to associate an external
optical unit 150 with the optical interconnect mesh 20 so as to
enable the external optical unit 150 to function in the network
architecture enabled by the optical interconnect mesh 20. The
external optical unit 150 is preferably associated with the optical
interconnect mesh 20 via ports 160 and 170 in the link adder 140.
By way of example, the external optical unit 150 provides optical
signals to the PIC device 10 via the port 160 and receives optical
signals from the PIC device 10 via the port 170. It is appreciated
that the link adder 140 may optionally include a switch (not shown)
which in an on state connects the external optical unit 150 to the
PIC device 10 and in an off state disconnects the external optical
unit 150 from the PIC device 10.
[0123] The external optical unit 150 preferably includes a
processing element (not shown) capable of performing network
processing operations that are associated with a conventional
network, such as detection of an address of the external optical
unit 150, re-transmission of information received at the external
optical unit 150, etc. The external optical unit 150 also
preferably includes at least one of the following (all not shown):
an external optical transceiver; an external optical network; an
external optical switch; an external optical router; an external
optical linecard; an external PIC device; an external optical
processing element; an external optical decoder; and a PIC
monitoring system.
[0124] The external optical unit 150 may additionally include an
isolator (not shown) for protecting a transmitting element (not
shown) of the external optical unit 150 from back reflections of
light from the reflecting optical element 70. Alternatively, the
isolator of the external optical unit 150 may be replaced by an
isolator (not shown) associated with the port 160 of the link adder
140.
[0125] In a case where the PIC device 10 and the external optical
unit 150 operate on optical signals having different
characteristics, an adapter 180 which interfaces to the link adder
140 and to the external optical unit 150 may preferably be used to
adapt characteristics of the optical signals. For example, if the
external optical unit 150 uses optical transceivers that transmit
at a first wavelength band, such as a wavelength band around 1.55
.mu.m, and the optical transceivers 30 in the PIC device 10
transmit at a second wavelength band, such as a wavelength band
around 0.85 .mu.m, the adapter 180 preferably converts wavelengths
of optical signals outputted from the external optical unit 150
towards the PIC device 10 to wavelengths in the second wavelength
band, and wavelengths of optical signals outputted from the PIC
device 10 towards the external optical unit 150 to wavelengths in
the first wavelength band. It is appreciated that wavelength
conversion is preferably performed by conventional wavelength
converters (not shown) in the adapter 180. It is further
appreciated that the adapter 180 may include other appropriate
means (not shown) for adapting other characteristics of the optical
signals.
[0126] In a case where the external optical unit 150 and the PIC
device 10 use optical signals having similar characteristics, the
adapter 180 is optional.
[0127] Preferably, the PIC device 10 is operatively associated with
a control and management system 190. The control and management
system 190 is external to the PIC device 10. Alternatively, part of
the control and management system 190 may be comprised in the PIC
device 10.
[0128] The control and management system 190 preferably controls
and manages the PIC device 10 via at least one of the following: an
electrical interconnect 200 connected to the interface unit 130 via
a port 210; and optical interconnects 220 and 230 respectively
connected to the bidirectional coupler 80 via ports 240 and 250 and
corresponding optical paths 65. In a case where the control and
management system 190 controls and manages the PIC device 10 via
the electrical interconnect 200, the electrical interconnect 200
preferably transfers control and management electronic signals from
the control and management system 190 to the optical transceivers
30, and response electronic signals from the optical transceivers
30 to the control and management system 190.
[0129] In a case where the control and management system 190
controls and manages the PIC device 10 via the optical
interconnects 220 and 230, the control and management system 190
preferably operates as an OE node that transmits and receives
information via the optical interconnect mesh 20. It is appreciated
that an isolator 260 is preferably used to protect a transmitting
portion of the control and management system 190 from back
reflections of light from the reflecting optical element 70.
[0130] It is further appreciated that the control and management
system 190 may also preferably control the adapter 180.
[0131] Preferably, the set of optical transceivers 30 includes at
least one optical transceiver 30 which is used for providing at
least one of communication protection and communication
restoration. Communication protection and communication restoration
are both types of recovery schemes as described in the
above-mentioned article entitled "IETF Work on Protection and
Restoration for Optical Networks", by David W. Griffith in Optical
Networks Magazine, July/August 2003, pages 101-106, the disclosure
of which is hereby incorporated herein by reference.
[0132] Preferably, at least one optical transceiver 30 in the set
of optical transceivers 30 which is not used for providing at least
one of communication protection and communication restoration and
the at least one optical transceiver 30 which is used for providing
at least one of communication protection and communication
restoration are at least partially comprised in separate layers of
the PIC device 10 and/or separate areas of the PIC device 10.
[0133] It is appreciated that the PIC device 10 may also preferably
include additional optical elements (not shown) that transmit and
receive optical signals via the network architecture of the PIC
device 10. The additional optical elements may include, for example
which is not meant to be limiting, at least one of the following:
at least one electro-optic (EO) switch; and at least one optical
processing element. Each additional optical element preferably
includes a processing element capable of performing network
processing operations that are associated with a conventional
network, such as detection of an address of the additional optical
element, re-transmission of information received at the additional
optical element, etc.
[0134] In operation, each optical transceiver 30 together with a
corresponding associated portion of the interface unit 130 and a
corresponding isolator 120 operates as an OE node in a network of
the PIC device 10 which is based on the network architecture
enabled by the optical interconnect mesh 20. The OE node preferably
uses the optical transmitter 40 or 60 of the optical transceiver 30
to transmit optical signals to other OE nodes of the PIC device 10,
and the optical receiver 50 of the optical transceiver 30 to
receive optical signals from other OE nodes of the PIC device 10.
The processing element associated with or comprised in the portion
of the interface unit 130 associated with the optical transceiver
30 provides processing capabilities to the OE node.
[0135] When an OE node transmits optical signals, the optical
signals propagate along one of the optical paths 65 of the optical
interconnect mesh 20 towards one of the ports 90 of the
bi-directional coupler 80. The optical signals are then directed to
the reflecting optical element 70 via the port 100 and the optical
path 110. The reflecting optical element 70 reflects the optical
signals back to the port 100 via the optical path 110. The
bi-directional coupler 80 then distributes such reflected optical
signals among all the optical receivers 50 via the ports 90 and
corresponding optical paths 65 of the optical interconnect mesh 20.
It is thus appreciated that the optical interconnect mesh 20 has a
structure which enables transmission by one OE node associated with
the optical interconnect mesh 20 to be received by all other OE
nodes associated with the optical interconnect mesh 20. Preferably,
optical transmission power of each optical transceiver 30 is
selected so as to take into account optical power distribution
according to a number of ports 90 in the bi-directional coupler
80.
[0136] It is appreciated that the bi-directional coupler 80 also
distributes the reflected optical signals among the optical
transmitters 40 and 60 but the isolators 120 preferably protect the
optical transmitters 40 and 60 from such back reflections of light
from the reflecting optical element 70.
[0137] Since in the network of the PIC device 10 a transmission by
one OE node is received by all other OE nodes, the network of the
PIC device 10 is capable of operating as a bus/broadcast network or
a star network.
[0138] In operation as a bus/broadcast network, the optical path
110 may be referred to as a bus to which all the OE nodes transmit
optical signals and from which all the OE nodes receive optical
signals. Multicast to only some of the OE nodes may be obtained by
broadcasting information with addresses of only some of the OE
nodes. Although all the OE nodes receive the information, only OE
nodes having one of the broadcasted addresses process the
information and all other OE nodes ignore the information. Unicast
may similarly be obtained by broadcasting information with an
address of only one OE node.
[0139] In operation as a star network, the processing capabilities
of the OE nodes are used and the reflecting optical element 70 may
be referred to as a central repeater having no processing
capabilities. Multicast to only some of the OE nodes may be
obtained by broadcasting information with addresses of only some of
the OE nodes. Although all the OE nodes receive the information,
only OE nodes having one of the broadcasted addresses process the
information and all other OE nodes ignore the information. Unicast
may similarly be obtained by broadcasting information with an
address of only one OE node.
[0140] It is appreciated that the network of the PIC device 10 is
also capable of operating as a ring network although such operation
is more complicated than operation as a bus/broadcast network or a
star network. In operation as a ring network, each OE node in the
PIC device 10 may transmit information with an address of only one
OE node, and all the other OE nodes are turned-off at a time when
the information is transmitted thus disabling broadcast. The OE
nodes are cyclically addressed so that a first OE node transmits
the information to a second OE node which, in turn, transmits the
information to a third OE node, and so on.
[0141] When two OE nodes communicate with each other, a receiving
OE node checks received information and if the received information
is addressed to the receiving OE node, the receiving OE node
processes the information. If the received information is not
addressed to the receiving OE node, the receiving OE node transmits
the received information to another OE node. Each OE node thus
operates as a repeater. Multicast may be obtained by associating
addresses of a plurality of OE nodes with the information and
instructing addressed OE nodes to process information addressed
thereto as well as to repeat and handover the information to other
OE nodes.
[0142] It is appreciated that the network of the PIC device 10 is
capable of operating as any one of the star network, the
bus/broadcast network and the ring network due to, inter alia, the
structure of the optical interconnect mesh 20. The structure of the
optical interconnect mesh 20 also enables a configurable network
architecture in which the PIC device 10 is enabled to be
reconfigured from a first network architecture to a second network
architecture. For example, if initially the PIC device 10 is
configured in the star network architecture, the PIC device 10 may
later be reconfigured, for example in response to an instruction
entered by an operator of the control and management system 190,
from the star network architecture to the bus/broadcast network
architecture or to the ring network architecture. Such
reconfiguration is performed, for example, by changing operation
modes of the optical transceivers 30 to correspond to the
reconfigured network architecture.
[0143] It is appreciated that the operation of the PIC device 10 is
preferably controlled and managed by the control and management
system 190.
[0144] It is further appreciated that communication among OE nodes
in the network of the PIC device 10 is not dependent upon specific
locations of the OE nodes in the PIC device 10. Rather,
communication among the OE nodes in the network of the PIC device
10 is enabled even if the OE nodes are spread throughout large
portions of the PIC device 10. In a case where electronic chips or
subsystems of electronic chips are associated with the OE nodes,
the electronic chips or the subsystems of electronic chips may
communicate with each other regardless of their actual locations in
the PIC device 10. It is appreciated that the electronic chips or
the subsystems of electronic chips preferably use conventional
network protocols for communication among them.
[0145] In a case where the PIC device 10 is comprised in a first
linecard, the PIC device 10 may communicate with another PIC device
(not shown) in a second linecard via the link adder 140 using
conventional network protocols thus enabling linecard-to-linecard
communication.
[0146] The network of the PIC device 10 also preferably enables
flexible assignment of optical transceivers 30 for providing at
least one of communication protection and communication
restoration. Since, as mentioned above, in the network of the PIC
device 10 a transmission by one OE node is received by all other OE
nodes, any optical transceiver 30 in an OE node may be assigned for
providing communication protection and/or communication restoration
for the entire network of the PIC device 10 or for a specific
optical transceiver 30 of a specific OE node without affecting the
other OE nodes.
[0147] If only a single channel wavelength is to be used for
communication protection and/or for communication restoration, the
single channel wavelength may be assigned for protection and/or for
restoration for the entire network of the PIC device 10 or for a
specific optical transceiver 30 of a specific OE node without
affecting the other OE nodes and also without affecting other
channel wavelengths that are used by the optical transceivers 30 in
the PIC device 30. It is appreciated that the single channel
wavelength or a plurality of channel wavelengths may be selected
for providing the communication protection and/or the communication
restoration over the single channel wavelength or the plurality of
channel wavelengths, respectively. Selection of the single channel
wavelength or the plurality of channel wavelengths may be carried
out in advance or dynamically based upon availability of the single
channel wavelength or the plurality of channel wavelengths.
[0148] Preferably, assignment of optical transceivers 30 for
providing at least one of communication protection and
communication restoration is performed by the control and
management system 190, and an indication of the assignment, as well
as an indication of which optical transceivers 30 are protected, is
flagged throughout the PIC device 10.
[0149] By way of example, which is not meant to be limiting, the
control and management system 190 may determine a first sub-group
of the set of optical transceivers 30 as a sub-group of active
optical transceivers for normal communication. In response to a
determination of the first sub-group, a second sub-group of the set
of optical transceivers 30 is preferably assigned as a protecting
sub-group of optical transceivers for providing at least one of
communication protection and communication restoration for the
first sub-group. Preferably, the control and management system 190
maintains an identification of the first sub-group and an
identification of the second sub-group.
[0150] It is appreciated that the second sub-group is preferably
automatically assigned as the protecting sub-group of optical
transceivers. By way of example, which is not meant to be limiting,
if the first sub-group includes half the number of optical
transceivers in the set of optical transceivers 30, the rest of the
optical transceivers in the set of optical transceivers 30 may
automatically be assigned as protecting optical transceivers.
[0151] Preferably, communication protection and communication
restoration may be applied as necessary to achieve recovery in case
of a communication failure. The communication failure may, for
example, occur due to failures in optical transceivers 30, which
failures may result from at least one of the following: an optical
fault; a thermal deviation fault; and an electronic fault. The
communication failure may apply to one channel wavelength or to a
plurality of channel wavelengths.
[0152] The recovery may be achieved according to one of well known
recovery schemes described in the above-mentioned article entitled
"IETF Work on Protection and Restoration for Optical Networks", by
David W. Griffith in Optical Networks Magazine, July/August 2003,
pages 101-106, the disclosure of which is hereby incorporated
herein by reference. For example, a 1+1 recovery scheme or a 1:1
recovery scheme may be used in the above-mentioned case where the
first sub- group includes half the number of optical transceivers
in the set of optical transceivers 30 and the rest of the optical
transceivers in the set of optical transceivers 30 are assigned as
protecting optical transceivers.
[0153] Preferably, each OE node may use one channel wavelength or a
plurality of channel wavelengths depending on whether the optical
transceiver 30 associated therewith uses one channel wavelength or
a plurality of channel wavelengths. The optical interconnect mesh
20 also enables use of one channel wavelength or a plurality of
channel wavelengths. Thus, the network of the PIC device 10 is
capable of using wavelength division multiplexing (WDM) of two or
more wavelengths in configurations employing coarse WDM (CWDM),
dense WDM (DWDM), and optical frequency division multiplexing
(OFDM).
[0154] Preferably, the PIC device 10 uses each of WDM, CWDM, DWDM
and OFDM in either a broadcast-and-select configuration or a
wavelength routing configuration. In the broadcast-and-select
configuration each OE node transmits over a separate channel
wavelength or over a separate set of channel wavelengths, and
wavelength division multiplexed transmissions from all the OE nodes
are received by all the OE nodes but each OE node processes only a
transmission provided over a channel wavelength assigned thereto or
transmissions provided over a set of channel wavelengths assigned
thereto. It is appreciated that assignment of a specific channel
wavelength or a specific set of channel wavelengths to an OE node
may be performed, for example, by instructing the optical receiver
50 of the OE node to tune to the specific channel wavelength or to
the specific set of channel wavelengths, respectively.
[0155] It is thus appreciated that when WDM or any of its variants
is used in the PIC device 10, more than one OE node may transmit at
a time provided that each transmitting OE node uses a separate
channel wavelength or a separate set of channel wavelengths.
[0156] In the wavelength routing configuration a lightpath between
a transmitting OE node and a receiving OE node is determined by a
channel wavelength and addresses of the transmitting OE node and
the receiving OE node. A transmission by the transmitting OE node
is preferably associated with the address of the receiving OE node.
Although the transmission is received by all the OE nodes in the
network of the PIC device 10, only the receiving OE node addressed
by the transmitting OE node may process the transmission
transmitted by the transmitting OE node and use it or forward it as
necessary.
[0157] It is appreciated that the PIC device 10 may be comprised in
a photonic switch (not shown) and used to switch and route optical
signals. For example, a first OE node in the PIC device 10 may
receive an optical packet either from a first element of the
photonic switch (not shown) or from a chip in the PIC device 10
which is associated with the first OE node and switch the optical
packet either to a second OE node of the PIC device 10 or to a
second element of the photonic switch. In such an application, the
photonic switch replaces the external optical unit 150 and
reception of the optical packet from the first element of the
photonic switch and transmission of the optical packet to the
second element of the photonic switch are preferably performed via
the link adder 140. The optical packet may include a fixed-length
optical packet, or an optical burst, that is a variable-length
optical packet.
[0158] In a case where at least some OE nodes in the PIC device 10
comprise multi-channel laser array modules, some of the
multi-channel laser array modules may use separate sets of
wavelengths. For example, a first multi-channel laser array module
may be capable of simultaneously transmitting over a first set of
channel wavelengths, and a second multi-channel laser array module
may be capable of simultaneously transmitting over a second set of
channel wavelengths, where the channel wavelengths of the second
set are different from the channel wavelengths of the first set. In
such a case, the first multi-channel laser array module and the
second multi-channel laser array module may simultaneously transmit
via the optical interconnect mesh 20, and a single optical receiver
50 may simultaneously receive transmissions provided by the first
multi-channel laser array module over the first set of channel
wavelengths and transmissions provided by the second multi-channel
laser array module over the second set of channel wavelengths.
[0159] The first and second multi-channel laser array modules may
be used for normal communication with the single optical receiver
50. Alternatively, the second multi-channel laser array module or a
portion thereof may be used for providing at least one of
communication protection and communication restoration for the
first multi-channel laser array module. For example, the first
multi-channel laser array module may transmit simultaneously over
channel wavelengths .lamda..sub.1, .lamda..sub.2, .lamda..sub.3 and
.lamda..sub.4 and the second multi-channel laser array module may
transmit simultaneously over channel wavelengths .lamda..sub.5,
.lamda..sub.6, .lamda..sub.7 and .lamda..sub.8. The channel
wavelengths .lamda..sub.1-.lamda..sub.7 may be used for normal
communication and .lamda..sub.8 may be used for any one of the
following: protection of communication over .lamda..sub.1 only;
protection of communication over any of
.lamda..sub.1-.lamda..sub.4; and protection of communication over
any of .lamda..sub.1-.lamda..sub.7.
[0160] Alternatively, more than one channel wavelength may be used
for communication protection. For example, .lamda..sub.4 may be
used for protection of communication over any of
.lamda..sub.5-.lamda..sub.7 and .lamda..sub.8 may be used for
protection of communication over any of
.lamda..sub.1-.lamda..sub.3. It is appreciated that in general it
is preferred, but not mandatory, to protect a channel wavelength
used by one multi-channel laser array module by a channel
wavelength used by another multi-channel laser array module.
[0161] The network of the PIC device 10 also preferably enables
verification of optical functionality of the optical transmitters
40 and 60 in the PIC device 10. Preferably, each of the optical
transmitters 40 and 60 is assigned an individual optical signal for
optical functionality verification. An optical transmitter 40 or
60, whose optical functionality is to be verified, preferably
transmits via the optical interconnect mesh 20 its individually
assigned optical signal and at least one of the plurality of
optical receivers 50 which receives the individually assigned
optical signal preferably determines whether the individually
assigned optical signal is correctly received. A determination that
the individually assigned optical signal is correctly received may
preferably be used to verify both optical functionality of the
optical transmitter 40 or 60 which transmits the individually
assigned optical signal and optical functionality of the at least
one of the plurality of optical receivers 50 which receives the
individually assigned optical signal.
[0162] The individually assigned optical signals are preferably
different from each other. Alternatively, at least some of the
individually assigned optical signals may have identical patterns
but be carried over separate channel wavelengths. In such a case,
the at least one of the plurality of optical receivers 50 which
receives the individually assigned optical signal also preferably
determines whether the individually assigned optical signal is
received over a correct channel wavelength. The individually
assigned optical signals may be fixed or alterable by an operator
of the control and management system 190. Preferably, each of the
individually assigned optical signals includes a digitally coded
optical signal.
[0163] Preferably, the OE nodes in the PIC device 10 may be
configured for operation with at least one of the following:
various optical switching methods; optical signals of various types
and formats; and optical signals coded in various line codes. For
example, which is not meant to be limiting, the OE nodes in the PIC
device 10 may be configured for operation with circuit switching or
optical packet switching, streamed optical signals or optical
packets, and return-to-zero (RZ) or non-return-to zero (NRZ) coded
optical signals. It is appreciated that such configurations of the
OE nodes in the PIC device 10 may, for example, be performed during
installation of the PIC device 10 and changed dynamically, for
example, by the operator of the control and management system
190.
[0164] In a case where the OE nodes of the PIC device 10 operate
with optical packets, an OE node in the PIC device 10 may
determine, from a plurality of optical packets, a first group of
optical packets that can be switched by a flow-switching technique
(FST) and a second group of optical packets that cannot be switched
by FST. FST is described, for example, in the above-mentioned
article entitled "Packet switching takes steps toward optical", by
Jeff Hecht in Laser Focus World, June 2002, pages 131-139, the
disclosure of which is hereby incorporated herein by reference.
[0165] Preferably, the OE node may switch the first group of
optical packets by using FST and the second group of optical
packets by using packet switching. It is appreciated that the first
group of optical packets may include at least one of the following:
at least one optical burst that exceeds a packet-length threshold;
and at least one optical packet that is combinable with other
optical packets. The packet-length threshold may preferably be
pre-selected.
[0166] It is appreciated that in the present invention the embedded
optical interconnect mesh 20 is used to enable a network
architecture that allows communication among various combinations
of optical transceivers 30 in the PIC device 10 and particularly
allows any optical transmitter 40 or 60 to communicate with any
optical receiver 50 via the optical interconnect mesh 20.
[0167] In accordance with a preferred embodiment of the present
invention the PIC device 10, and particularly the optical
transmitters 40 and 60, include elements that aid in operation in
an environment in which a plurality of optical transceivers operate
simultaneously, for example, to perform a plurality of tasks and/or
to communicate various data items. It is appreciated that such
elements are also appropriate for and usable with PIC devices that
employ separate optical interconnects and optical communication
systems that employ a plurality of optical transmitters and optical
receivers.
[0168] The elements that aid in operation in an environment in
which a plurality of optical transceivers operate simultaneously
are preferably comprised in or associated with tunable laser
modules and multi-channel laser array modules that are comprised in
the optical transmitters 40 and 60. The elements that aid in
operation in an environment in which a plurality of optical
transceivers operate simultaneously, as well as features enabled by
such elements, are described herein below with reference to FIGS. 2
and 3.
[0169] Tunable laser modules have been subject to intensive
standardization efforts which resulted in a series of tunable laser
standards known as Implementation Agreements OIF-TL-01.1,
OIF-TLMSA-01.1, and OIF-ITLA-MSA-01.1, the disclosures of which are
hereby incorporated herein by reference. However, tunable laser
modules that operate in an environment in which a plurality of
optical transceivers operate simultaneously may require additional
elements and features that are not provided by the above-mentioned
tunable laser standards.
[0170] Reference is now additionally made to FIG. 2, which is a
simplified block diagram illustration of a preferred implementation
of a tunable laser module 300 constructed and operative in
accordance with a preferred embodiment of the present
invention.
[0171] The tunable laser module 300 preferably includes a light
emitter 310 and electronic circuitry 320. For simplicity,
additional elements of the tunable laser module 300 which are well
known in the art, such as interfaces and a heat sink, are not shown
in FIG. 2.
[0172] The light emitter 3 10 is preferably capable of selectively
transmitting in any one of a plurality of channel wavelengths
within at least one wavelength band.
[0173] In accordance with a preferred embodiment of the present
invention the electronic circuitry 320 includes at least one of the
following registers or a combination thereof: a register 330; a
register 340; a register 350; and a register 360. Each of the
registers 330, 340, 350 and 360 may be implemented by any
appropriate register, such as a register assigned as a register for
user data storage (User1 register) in accordance with the
above-mentioned tunable laser standards, or a register assigned as
a manufacturer specific register in accordance with the
above-mentioned tunable laser standards, or any other appropriate
unassigned and/or available register. Each of the registers 330,
340, 350 and 360 may alternatively be implemented by a plurality of
appropriate registers. It is appreciated that the registers 330,
340, 350 and 360 may be implemented by registers which provide
various storage areas.
[0174] The register 330 preferably stores an indication that the
tunable laser module 300 is assigned to provide at least one of
communication protection and communication restoration. The at
least one of communication protection and communication restoration
is preferably provided for at least one of the following: at least
a portion of a separate optical transmitter; and at least a portion
of an optical communication system. The separate optical
transmitter preferably includes any appropriate optical transmitter
comprising, for example, at least one of the following: a VCSEL; a
LED; an EEL; a tunable laser; a fixed-channel laser; and a tunable
VCSEL.
[0175] The indication preferably includes an identification of at
least one of the following: the at least a portion of the separate
optical transmitter; and the at least a portion of the optical
communication system. Thus, for example, in a case where the
tunable laser module 300 is comprised in a first optical
transmitter 40 in the PIC device 10, the register 330 may store an
indication indicating that the first optical transmitter 40, or a
portion thereof, is assigned to provide at least one of
communication protection and communication restoration for a second
optical transmitter 40 in the PIC device 10 or for the entire
network of the PIC device 10, and an identification of the second
optical transmitter 40 or the network of the PIC device 10,
respectively.
[0176] Preferably, the register 330 also stores an identification
of at least one channel wavelength over which the at least one of
communication protection and communication restoration is
provided.
[0177] It is appreciated that such an indication, as well as the
identification of which portion of the optical transmitter or
portion of the optical communication system is to be protected and
the at least one channel wavelength over which the at least one of
communication protection and communication restoration is provided,
is useful in cases where due to a large number of optical
transceivers in an environment in which a plurality of optical
transceivers operate simultaneously it is difficult for an operator
to determine which optical transmitters are assigned to provide
protection and/or restoration, which transceivers are protected,
which channel wavelengths are used for protection and/or
restoration, and whether changes in assignments of optical
transmitters and assignments of channel wavelengths for
communication are allowed.
[0178] In such cases, the operator may, for example, transmit a
query to the tunable laser module 300 and receive a response with
an indication as stored in the register 330, which indication may,
for example, indicate that the tunable laser module 300 is assigned
to provide communication protection for a specific optical
transmitter 40, an identification of the specific optical
transmitter 40, and an identification of, for example, a channel
wavelength .lamda..sub.1 over which communication protection and
communication restoration are provided. The operator may then mark
a first optical transceiver 30 in which the specific optical
transmitter 40 is comprised as a protected optical transceiver, a
second optical transceiver 30 in which the tunable laser module 300
is comprised as a protecting optical transceiver, and .lamda..sub.1
as a channel wavelength over which protection and restoration are
provided. Such marking may then, for example, be used to avoid
using the protecting optical transceiver, the protected optical
transceiver, and .lamda..sub.1 for other purposes.
[0179] It is appreciated that transmission of such a query and use
of the response for such marking may also be performed in PIC
devices that employ separate optical interconnects and in optical
communication systems that employ a plurality of optical
transmitters and optical receivers.
[0180] The register 340 preferably stores an indication identifying
a location within a PIC device in which a circuit structure which
is at least partially embedded in the PIC device is located, where
the circuit structure comprises at least a portion of the tunable
laser module 300. The indication identifying the location within
the PIC device preferably includes at least one of the following:
an indication of a layer of the PIC device in which the circuit
structure is comprised; and an indication of an area of the PIC
device in which the circuit structure is located. It is appreciated
that such an indication is useful in the PIC device 10 as well as
in PIC devices that employ separate optical interconnects, for
example, for determining a location of the tunable laser module 300
in cases where a plurality of optical transceivers are distributed
in various PIC areas and/or PIC layers.
[0181] The register 350 preferably stores an identification of at
least one channel wavelength of the plurality of channel
wavelengths which is unusable by the tunable laser module 300. The
at least one unusable channel wavelength may, for example, be
unusable due to at least one of the following: a warning fault; a
fatal fault; a constraint of a system in which the tunable laser
module 300 is comprised; and an instruction of an operator. Each of
the warning fault and the fatal fault preferably includes at least
one of the following: an optical fault; a thermal deviation fault;
and an electronic fault. The at least one unusable channel
wavelength may include at least one channel wavelength which is
temporarily unusable.
[0182] It is appreciated that such an identification of unusable
channel wavelengths is useful for avoiding unsuccessful attempts to
use unusable channel wavelengths in the PIC device 10 as well as in
PIC devices that employ separate optical interconnects and in
optical communication systems that employ a plurality of optical
transmitters and optical receivers.
[0183] The register 360 preferably stores at least one bit enabling
return from a current channel grid configuration to at least one of
the following: a previous channel grid configuration; and a default
channel grid configuration. The default channel grid configuration
may preferably be preset or user-selected. Presetting of the
default channel grid configuration may occur once, for example
during installation of the tunable laser module 300, or more than
once, for example each time a change occurs in conditions at the
tunable laser module 300, such as a change in temperature
conditions. It is appreciated that return to the previous channel
grid configuration or to the default channel grid configuration is
preferably performed in response to a return-to-grid (RTG)
instruction.
[0184] Enabling return from a current channel grid configuration to
a previous channel grid configuration or to a default channel grid
configuration is useful, for example, in cases where the current
channel grid configuration includes unusable channel wavelengths
whereas the previous channel grid configuration and the default
channel grid configuration do not include unusable channel
wavelengths. In such cases, the operator may attempt to change the
current channel grid but if such an attempt results in another
channel grid which includes unusable channel wavelengths, the
operator may prefer to return to the previous channel grid
configuration or to the default channel grid configuration by using
the at least one bit enabling return from a current channel grid
configuration.
[0185] It is appreciated that the at least one bit enabling return
from a current channel grid configuration is useful in the PIC
device 10 as well as in PIC devices that employ separate optical
interconnects and in optical communication systems that employ a
plurality of optical transmitters and optical receivers.
[0186] Reference is now additionally made to FIG. 3, which is a
simplified block diagram illustration of a preferred implementation
of a multi-channel laser array module 400 constructed and operative
in accordance with a preferred embodiment of the present
invention.
[0187] The multi-channel laser array module 400 preferably includes
a light emitting array 410, a light receiving array 420, and
electronic circuitry 430. For simplicity, additional elements of
the multi-channel laser array module 400 which are well known in
the art, such as interfaces and heat sinks, are not shown in FIG.
3.
[0188] The light emitting array 410 is preferably capable of
simultaneously transmitting in a plurality of channel wavelengths
within at least one wavelength band. The light emitting array 410
preferably includes at least one of the following: a VCSEL array; a
tunable VCSEL array; an EEL array; an assembly combining a
plurality of fixed-channel lasers; and an assembly combining a
plurality of tunable single-channel lasers.
[0189] The light receiving array 420 is preferably capable of
simultaneously receiving in a plurality of channel wavelengths
within at least one wavelength band. The light receiving array 420
preferably includes at least one of the following: a PD array; and
a photo-detector array. Each PD in the PD array preferably includes
at least one of the following: a p-i-n photodiode; and an APD. Each
photo-detector in the photo-detector array preferably includes an
MSM photo-detector.
[0190] In accordance with a preferred embodiment of the present
invention the electronic circuitry 430 includes at least one of the
following registers or a combination thereof: a register 440; a
register 450; a register 460; and a register 470. Each of the
registers 440, 450, 460 and 470 may be implemented by any
appropriate register or by a plurality of appropriate registers. It
is appreciated that the registers 440, 450, 460 and 470 may be
implemented by registers which provide various storage areas.
[0191] The register 440 preferably stores an identification of at
least one channel wavelength of the plurality of channel
wavelengths which is unusable by the multi-channel laser array
module 400. The at least one unusable channel wavelength may, for
example, be unusable due to at least one of the following: a
warning fault; a fatal fault; a constraint of a system in which the
multi-channel laser array module 400 is comprised; and an
instruction of an operator. Each of the warning fault and the fatal
fault preferably includes at least one of the following: an optical
fault; a thermal deviation fault; and an electronic fault. The at
least one unusable channel wavelength may include at least one
channel wavelength which is temporarily unusable.
[0192] It is appreciated that such an identification of unusable
channel wavelengths is useful for avoiding unsuccessful attempts to
use unusable channel wavelengths in the PIC device 10 as well as in
PIC devices that employ separate optical interconnects and in
optical communication systems that employ a plurality of optical
transmitters and optical receivers.
[0193] The register 450 preferably stores an indication identifying
a location within a PIC device in which a circuit structure which
is at least partially embedded in the PIC device is located, where
the circuit structure comprises at least a portion of the
multi-channel laser array module 400. The indication identifying
the location within the PIC device preferably includes at least one
of the following: an indication of a layer of the PIC device in
which the circuit structure is comprised; and an indication of an
area of the PIC device in which the circuit structure is located.
It is appreciated that such an indication is useful in the PIC
device 10 as well as in PIC devices that employ separate optical
interconnects, for example, for determining a location of the
multi-channel laser array module 400 in cases where a plurality of
optical transceivers are distributed in various PIC areas and/or
PIC layers.
[0194] The register 460 preferably stores an indication that at
least one single-channel laser in the multi-channel laser array
module 400 is assigned to provide at least one of communication
protection and communication restoration. The at least one of
communication protection and communication restoration is
preferably provided for at least one of the following: at least a
portion of a separate optical transmitter; at least a portion of an
optical communication system; and a portion of the multi-channel
laser array module 400 that does not include the at least one
single-channel laser. The separate optical transmitter preferably
includes any appropriate optical transmitter comprising, for
example, at least one of the following: a VCSEL; a LED; an EEL; a
tunable laser; a fixed-channel laser; and a tunable VCSEL.
[0195] The indication preferably includes an identification of at
least one of the following: the at least a portion of the separate
optical transmitter; the at least a portion of the optical
communication system; the at least one single-channel laser; and
the portion of the multi-channel laser array module 400 that does
not include the at least one single-channel laser.
[0196] In a case where the multi-channel laser array module 400
includes a tunable multi-channel laser array module, the register
460 may also preferably store an identification of at least one
channel wavelength over which the at least one of communication
protection and communication restoration is provided.
[0197] It is appreciated that such an indication is, for example,
useful in cases where due to a large number of multi-channel
optical transceivers in an environment in which a plurality of
optical transceivers operate simultaneously it is difficult for an
operator to determine which portions of optical transmitters are
assigned to provide protection and/or restoration, which portions
of optical transmitters are protected and which optical
transceivers are protected, which channel wavelengths are used for
protection and/or restoration, and whether changes in assignments
of optical transmitters and assignments of channel wavelengths for
communication are allowed.
[0198] In such cases, the operator may, for example, transmit a
query to the multi-channel laser array module 400 and receive a
response with an indication as stored in the register 460, which
indication may, for example, indicate that a single-channel laser
in the multi-channel laser array module 400 that operates at a
wavelength .lamda..sub.1 is assigned to provide communication
protection for another single-channel laser in the multi-channel
laser array module 400 that operates at a wavelength .lamda..sub.2
and for a specific optical transmitter 40. The operator may then
mark the specific optical transmitter 40 and the laser operating at
.lamda..sub.2 as protected, and the laser operating at
.lamda..sub.1 as a protecting laser. Such marking may then, for
example, be used to avoid using the laser operating at
.lamda..sub.1 for a different task.
[0199] It is appreciated that transmission of such a query and use
of the response for such marking may also be performed in PIC
devices that employ separate optical interconnects and in optical
communication systems that employ a plurality of optical
transmitters and optical receivers.
[0200] The register 470 is particularly useful in a case where the
multi-channel laser array module 400 includes a tunable
multi-channel laser array module. In such a case, the register 470
is preferably used as the register 360 of FIG. 2 to store at least
one bit enabling return from a current channel grid configuration
to at least one of the following: a previous channel grid
configuration; and a default channel grid configuration. The
default channel grid configuration may preferably be preset or
user-selected. Presetting of the default channel grid configuration
may occur once, for example during installation of the
multi-channel laser array module 400, or more than once, for
example each time a change occurs in conditions at the
multi-channel laser array module 400, such as a change in
temperature conditions. It is appreciated that return to the
previous channel grid configuration or to the default channel grid
configuration is preferably performed in response to a
return-to-grid (RTG) instruction.
[0201] Enabling return from a current channel grid configuration to
a previous channel grid configuration or to a default channel grid
configuration is useful, for example, in cases where the current
channel grid configuration includes unusable channel wavelengths
whereas the previous channel grid configuration and the default
channel grid configuration do not include unusable channel
wavelengths. In such cases, the operator may attempt to change the
current channel grid but if such an attempt results in another
channel grid which includes unusable channel wavelengths, the
operator may prefer to return to the previous channel grid
configuration or to the default channel grid configuration by using
the at least one bit enabling return from a current channel grid
configuration.
[0202] It is appreciated that the at least one bit enabling return
from a current channel grid configuration is useful in the PIC
device 10 as well as in PIC devices that employ separate optical
interconnects and in optical communication systems that employ a
plurality of optical transmitters and optical receivers.
[0203] Reference is now made to FIG. 4, which is a simplified
flowchart illustration of a preferred method of operation of the
PIC device 10 of FIG. 1.
[0204] A PIC device is preferably provided (step 600). Preferably,
an optical interconnect mesh is embedded (step 610) within the PIC
device, where the optical interconnect mesh is structured to enable
at least one of the following network architectures: a star network
architecture; a bus/broadcast network architecture; and a ring
network architecture.
[0205] Reference is now made to FIG. 5, which is a simplified
flowchart illustration of another preferred method of operation of
the PIC device 10 of FIG. 1.
[0206] Preferably, an optical interconnect mesh is embedded (step
700) within a PIC device, where the optical interconnect mesh is
structured to enable a configurable network architecture. Then,
reconfiguration from a first network architecture to a second
network architecture is enabled (step 710). Each of the first
network architecture and the second network architecture preferably
includes one of the following network architectures: a star network
architecture; a bus/broadcast network architecture; and a ring
network architecture.
[0207] Reference is now made to FIG. 6, which is a simplified
flowchart illustration of a preferred method of operation of the
tunable laser module 300 of FIG. 2.
[0208] A tunable laser module is preferably provided (step 800).
Preferably, an indication that the tunable laser module is assigned
to provide at least one of communication protection and
communication restoration is stored (step 810) and the at least one
of communication protection and communication restoration is
preferably enabled and provided for at least one of the following:
at least a portion of a separate optical transmitter; and at least
a portion of an optical communication system. The indication is
preferably stored in at least one of the following: a register of
the tunable laser module; a register of the separate optical
transmitter; and a control and management system of the optical
communication system.
[0209] The indication preferably includes an identification of at
least one of the following: the at least a portion of the separate
optical transmitter; and the at least a portion of the optical
communication system. Additionally, an identification of at least
one channel wavelength over which the at least one of communication
protection and communication restoration is provided may also be
stored together with the indication.
[0210] Preferably, each of the tunable laser module and the
separate optical transmitter may be comprised in any one of the
following: the PIC device 10 of FIG. 1; a PIC device that employs
separate optical interconnects; and an optical communication system
that employs a plurality of optical transmitters and optical
receivers.
[0211] Reference is now made to FIG. 7, which is a simplified
flowchart illustration of a preferred method of operation of any of
the tunable laser module 300 of FIG. 2 and the multi-channel laser
array module 400 of FIG. 3.
[0212] Preferably, a circuit structure comprising at least a
portion of an optical transmitter is at least partially embedded in
a PIC device (step 900). The optical transmitter preferably
includes at least one of the following: a tunable laser module; and
a multi-channel laser array module. Preferably, an indication
identifying a location within the PIC device in which the circuit
structure is located is stored (step 910).
[0213] Reference is now made to FIG. 8, which is a simplified
flowchart illustration of another preferred method of operation of
the tunable laser module 300 of FIG. 2.
[0214] Preferably, a tunable laser module which is capable of
selectively transmitting in any one of a plurality of channel
wavelengths within at least one wavelength band is provided (step
1000). Then, an identification of at least one channel wavelength
of the plurality of channel wavelengths which is unusable by the
tunable laser module is preferably stored (step 1010).
[0215] Reference is now made to FIG. 9, which is a simplified
flowchart illustration of yet another preferred method of operation
of the tunable laser module 300 of FIG. 2.
[0216] Preferably, a tunable laser module is provided (step 1100).
At least one bit which enables return to a state is preferably
stored (step 1110). The state preferably includes a channel grid
configuration state of the tunable laser module, and the at least
one bit preferably enables return from a current channel grid
configuration to at least one of the following: a previous channel
grid configuration; and a default channel grid configuration. It is
appreciated that the tunable laser module may include a tunable
multi-channel laser array module in which case the method of FIG. 9
is also applicable to each tunable single-channel laser in the
tunable multi-channel laser array module as well as to the entire
tunable multi-channel laser array module.
[0217] Reference is now made to FIG. 10, which is a simplified
flowchart illustration of a preferred method of operation of the
multi-channel laser array module 400 of FIG. 3.
[0218] Preferably, a multi-channel laser array module which is
capable of simultaneously transmitting in a plurality of channel
wavelengths within at least one wavelength band is provided (step
1200). Then, an identification of at least one channel wavelength
of the plurality of channel wavelengths which is unusable by the
multi-channel laser array module is preferably stored (step
1210).
[0219] Reference is now made to FIG. 11, which is a simplified
flowchart illustration of another preferred method of operation of
the multi-channel laser array module 400 of FIG. 3.
[0220] A multi-channel laser array module is preferably provided
(step 1250). Preferably, an indication that at least one
single-channel laser in the multi-channel laser array module is
assigned to provide at least one of communication protection and
communication restoration is stored (step 1260). It is appreciated
that the at least one of communication protection and communication
restoration may be provided for at least one of the following: at
least a portion of a separate optical transmitter; at least a
portion of an optical communication system; and a portion of the
multi-channel laser array module that does not include the at least
one single-channel laser.
[0221] Reference is now made to FIG. 12, which is a simplified
flowchart illustration of a preferred method of verifying optical
functionality of an optical transmitter in the PIC device 10 of
FIG. 1.
[0222] A PIC device which comprises a plurality of optical
transmitters and a plurality of optical receivers is preferably
provided (step 1300). An optical transmitter, whose optical
functionality is to be verified, preferably transmits (step 1310)
via the PIC device an optical signal which is individually assigned
to the optical transmitter. Then, a determination is made (step
1320) of whether the individually assigned optical signal is
correctly received at at least one of the plurality of optical
receivers.
[0223] Reference is now made to FIG. 13, which is a simplified
flowchart illustration of a preferred method for providing at least
one of communication protection and communication restoration in
the PIC device 10 of FIG. 1.
[0224] Preferably, an optical interconnect mesh is embedded within
a PIC device (step 1400). The optical interconnect mesh is
preferably structured to enable a network architecture in which
optical transceivers associated with the optical interconnect mesh
communicate with each other. A first sub-group of the optical
transceivers is preferably determined (step 1410) as a sub-group of
active optical transceivers for use in normal communication. In
response to a determination of the first sub-group, a second
sub-group of the optical transceivers is preferably assigned (step
1420), for example automatically, as a protecting sub-group of
optical transceivers for providing at least one of communication
protection and communication restoration for the first sub-group of
the optical transceivers. It is appreciated that an identification
of the first sub-group and an identification of the second
sub-group may preferably be provided to a control and management
system and maintained in the control and management system.
[0225] Reference is now made to FIG. 14, which is a simplified
flowchart illustration of a preferred optical receiving method
useful with the PIC device 10 of FIG. 1.
[0226] Preferably, a first multi-channel laser array module and a
second multi-channel laser array module are embedded in a PIC
device (step 1500). The first multi-channel laser array module is
preferably capable of simultaneously transmitting over a first set
of channel wavelengths, and the second multi-channel laser array
module is preferably capable of simultaneously transmitting over a
second set of channel wavelengths, where the channel wavelengths of
the second set are different from the channel wavelengths of the
first set.
[0227] Preferably, transmissions provided by the first
multi-channel laser array module over the first set of channel
wavelengths and transmissions provided by the second multi-channel
laser array module over the second set of channel wavelengths are
simultaneously received (step 1510) at an optical receiver in the
PIC device via an optical interconnect mesh in the PIC device which
interconnects the optical receiver to the first multi-channel laser
array module and to the second multi-channel laser array
module.
[0228] Reference is now made to FIG. 15, which is a simplified
flowchart illustration of a preferred optical switching method
useful with the PIC device 10 of FIG. 1.
[0229] A plurality of optical packets is preferably provided (step
1600). Preferably, a first group of optical packets that can be
switched by a flow-switching technique (FST) and a second group of
optical packets that cannot be switched by FST are determined (step
1610) from the plurality of optical packets. Then, the first group
of optical packets is switched by using FST and the second group of
optical packets is switched by using packet switching (step 1620).
The first group of optical packets preferably includes at least one
of the following: at least one optical burst that exceeds a
packet-length threshold; and at least one optical packet that is
combinable with other optical packets. The packet-length threshold
may preferably be preset.
[0230] It is appreciated that various features of the invention
which are, for clarity, described in the contexts of separate
embodiments may also be provided in combination in a single
embodiment. Conversely, various features of the invention which
are, for brevity, described in the context of a single embodiment
may also be provided separately or in any suitable
sub-combination.
[0231] It will be appreciated by persons skilled in the art that
the present invention is not limited by what has been particularly
shown and described hereinabove. Rather the scope of the invention
is defined by the claims that follow:
* * * * *
References