U.S. patent application number 15/953765 was filed with the patent office on 2019-10-17 for comb laser arrays for dwdm interconnects.
The applicant listed for this patent is HEWLETT PACKARD ENTERPRISE DEVELOPMENT LP. Invention is credited to Raymond G. Beausoleil, Marco Fiorentino, Geza Kurczveil, Mir Ashkan Seyedi.
Application Number | 20190317286 15/953765 |
Document ID | / |
Family ID | 68063632 |
Filed Date | 2019-10-17 |
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United States Patent
Application |
20190317286 |
Kind Code |
A1 |
Seyedi; Mir Ashkan ; et
al. |
October 17, 2019 |
COMB LASER ARRAYS FOR DWDM INTERCONNECTS
Abstract
A photonic integrated circuit package includes two arrays or
sets of integrated comb laser modules that are bonded to a silicon
interposer. Each comb laser of an array has a common or overlapping
spectral range, with each laser in the array being optically
coupled to a local optical bus. The effective spectral range of the
lasers in each array are different, or distinct, as to each array.
An optical coupler is disposed within the silicon interposer and is
optically coupled to each of the local optical buses. An ASIC
(application specific integrated circuit) is bonded to the silicon
interposer and provides control and operation of the comb laser
modules.
Inventors: |
Seyedi; Mir Ashkan; (San
Francisco, CA) ; Fiorentino; Marco; (Mountain View,
CA) ; Kurczveil; Geza; (Goleta, CA) ;
Beausoleil; Raymond G.; (Seattle, WA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HEWLETT PACKARD ENTERPRISE DEVELOPMENT LP |
Houston |
TX |
US |
|
|
Family ID: |
68063632 |
Appl. No.: |
15/953765 |
Filed: |
April 16, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G02B 6/4249 20130101;
H01S 3/1305 20130101; H01S 3/131 20130101; G02B 6/4286 20130101;
H01S 3/2391 20130101; H04B 10/506 20130101; H04B 10/503 20130101;
G02B 6/43 20130101 |
International
Class: |
G02B 6/43 20060101
G02B006/43; H01S 3/13 20060101 H01S003/13; H01S 3/131 20060101
H01S003/131; H01S 3/23 20060101 H01S003/23; G02B 6/42 20060101
G02B006/42 |
Claims
1. A photonic integrated circuit package, comprising: a silicon
interposer; a first array of two or more comb laser modules bonded
to the silicon interposer, wherein the comb laser modules of the
first array have a common spectral output range; a second array of
two or more comb laser modules bonded to the silicon interposer,
wherein the comb laser modules of the second array have a common
spectral output range; an optical coupler provided within the
silicon interposer, the optical coupler optically coupled to each
of the first and second arrays of comb laser modules; and an ASIC
(application specific integrated circuit) bonded to the silicon
interposer, the ASIC electronically coupled to each comb laser
module of the first and second arrays, wherein the ASIC is further
configured to detect failure of one of the two or more comb laser
modules in the first array or the second array, and switch
operation to another of the two or more comb laser modules in the
same array as the detected failure.
2. The photonic integrated circuit package of claim 1, wherein each
comb laser module comprises an optical power monitor electronically
coupled to the ASIC.
3. The photonic integrated circuit package of claim 1, wherein the
comb laser modules of the first array have a spectral range of
emission different than a spectral range of emission of the comb
laser modules of the second array.
4. The photonic integrated circuit package of claim 1, wherein the
ASIC is configured to switch operation from a first comb laser in
the first array to a second comb laser in the first array.
5. The photonic integrated circuit package of claim 4, wherein the
ASIC is further configured to receive an instruction to switch over
to a specific comb laser module in the first array.
6. The photonic integrated circuit package of claim 4, wherein the
ASIC is further configured to switch operation from a first comb
laser in the second array to a second comb laser in the second
array.
7. The photonic integrated circuit package of claim 4, wherein the
ASIC is further configured to detect the failure of the one of the
two or more comb laser modules in the first array.
8. The photonic integrated circuit package of claim 1, wherein the
ASIC is configured to detect the operating power output of each of
the comb laser modules.
9. The photonic integrated circuit package of claim 1, wherein a
first comb laser module of the first array has a spectral range
bandwidth of emission of between 7 nm to 11 nm.
10. The photonic integrated circuit package of claim 1, wherein a
combined spectral range of the comb laser modules of the first
array and the comb laser modules of the second array have a
spectral range bandwidth of emission of between 14 nm to 22 nm.
11. A method for controlling a first and second array of comb laser
modules disposed on a silicon interposer, the method comprising:
providing power to a first comb laser module in the first array of
comb laser modules, the comb laser modules of the first array
having a common spectral output range; providing power to a first
comb laser module in a second array of comb laser modules, the comb
laser modules of the second array having a common spectral output
range; determining a switch over event for the first array; and
upon determining a switch over event, switching over operation of
the first comb laser module in the first array to operation of a
second comb laser module in the first array.
12. The method of claim 11, wherein determining a switch over event
comprises: monitoring the optical power for the first comb laser
module; and detecting that the optical power for the first comb
laser module is below a threshold power output value.
13. The method of claim 11, wherein switching over operation
comprises: ceasing data transmission via the first comb laser
module; and beginning data transmission via the second comb laser
module.
14. The method of claim 11, further determining a switch over event
comprises: receiving an instruction to switch operation to a
particular comb laser module of the first array.
15. The method of claim 11, further comprising: determining a
switch over order for each comb laser module in an array; and
switching over to a second comb laser module in the first array
based on the determined switch over order.
16. The method of claim 15, wherein determining a switch over order
comprises: for each comb laser module in an array: powering on the
comb laser module with a specified voltage; and recording a peak
power of the comb laser module.
17. The method of claim 11, wherein the comb laser modules of the
first array have a spectral range of emission different than a
spectral range of emission of the comb laser modules of the second
array.
18. The method of claim 11, wherein the first comb laser module of
the first array has a spectral range bandwidth of emission of
between 7 nm to 11 nm, and the first comb laser module of the
second array has a spectral range bandwidth of emission of between
7 nm to 11 nm.
19. The method of claim 11, wherein a combined spectral range of
the first comb laser module of the first array and the first comb
laser module of the second array have a spectral range bandwidth of
emission of between 14 nm to 22 nm.
20. The method of claim 11, further comprising: identifying the
first comb laser module as inoperative; and disabling the first
comb laser module from subsequent use.
Description
BACKGROUND
[0001] Dense Wavelength Division Multiplexing (DWDM) is an optical
multiplexing technology allowing transmission of data from
different sources onto an optical fiber. DWDM multiplexing allows
for about 96 wavelengths, or transmission channels, based on the
particular channel spacing. Comb lasers are particularly suited for
use with DWDM silicon photonic transmitters, such as a DWDM
interconnect device. The comb laser generates a low-noise
multi-spectral output of equidistant spectral lines. As the
comb-laser has an effective, or limited spectral range, multiple
comb lasers of different frequency domains are needed to achieve
broad frequency coverage to increase available channels.
[0002] The comb-lasers may have an effective life where constant
use subjects the comb laser to thermal fluctuations thereby causing
the operating characteristics of the laser to change overtime. In
certain cases, a comb laser may require additional power to produce
the same optical power output than when the laser was first used.
In other cases, the comb-laser may fail and need replacement. In
either situation, components of the DWDM interconnect, or a comb
laser itself, must be replaced. Replacement of a component, or the
comb laser, typically requires placing the interconnect into an
off-line mode thereby disrupting the data transmission through the
interconnect device, and manually replacing the defective
component.
BRIEF DESCRIPTION OF THE DRAWINGS
[0003] The present disclosure is best understood from the following
detailed description when read with the accompanying Figures. It is
emphasized that, in accordance with the standard practice in the
industry, various features are not drawn to scale. In fact, the
dimensions of the various features may be arbitrarily increased or
reduced for clarity of discussion.
[0004] FIG. 1 is a diagram of an exemplary photonic integrated
circuit package according to one example of the principles
disclosed herein.
[0005] FIG. 2 is a diagram of an exemplary photonic integrated
circuit package according to one example of the principles
disclosed herein.
[0006] FIG. 3 is a diagram of a method flow-chart illustrating
switch over from a comb laser module within an array of comb laser
modules.
DETAILED DESCRIPTION
[0007] Illustrative embodiments of the subject matter claimed below
will now be disclosed. In the interest of clarity, not all features
of an actual implementation are described in this specification. It
will be appreciated that in the development of any such actual
embodiment, numerous implementation-specific decisions must be made
to achieve the developers' specific goals, such as compliance with
system-related and business-related constraints, which will vary
from one implementation to another. Moreover, it will be
appreciated that such a development effort, even if complex and
time-consuming, would be a routine undertaking for those of
ordinary skill in the art having the benefit of this
disclosure.
[0008] Embodiments of the present disclosure are directed to a
photonic integrated circuit package. Two or more arrays or sets of
integrated comb laser modules are bonded to a silicon interposer.
Each comb laser module of the first array has a common spectral
range. The comb laser modules of the first array are each optically
coupled to a first optical bus. Each comb laser module of the
second array has a common spectral range. The comb laser modules of
the second array are each optically coupled to a second optical
bus. The spectral range of the comb laser modules of the first
array, and the spectral range of the comb laser modules of the
second array have different frequency domains. An optical coupler
is provided within the silicon interposer. The optical coupler is
optically coupled to each of the first and second optical buses. An
ASIC (application specific integrated circuit) is bonded to the
silicon interposer. The ASIC is electronically coupled individually
to each of the comb laser modules in the first and second arrays.
The ASIC provides control and operation of the comb laser
modules.
[0009] Other embodiments of the present disclosure include a
system, method and computer readable media controlling multiple
arrays of comb laser modules that are disposed on a silicon
interposer. The control circuitry of the silicon interposer
provides power to a first comb laser module in a first array of
comb laser modules. The comb laser modules of the first array have
a common spectral output range. The control circuitry of the
silicon interposer provides power to a first comb laser module in a
second array of comb laser modules. The comb laser modules of the
second array have a common spectral output range. The control
circuitry determines the occurrence of a switch over event to
switch over from one comb laser modules in an array to another comb
laser module in the array. Upon determining a switch over event,
the control circuitry switches over operation of a primary
operative comb laser module to a secondary or backup laser module
in the respective array. The switch over event, for example, may be
the detection of a failing or failed comb laser module in an array,
the detection that the power output of a comb laser module is below
a specified threshold level based for a given input voltage, or the
receipt of instructions to switch over to a specified comb laser
module in the array.
[0010] Switching from one comb laser module in an array may be done
in a sequential manner where the next comb laser module in an array
is utilized when the switch over event occurs. A preferred switch
over order may be determined by a diagnostic process performed by
the control circuitry where the switch over order for the comb
laser modules in an array is determined. The preferred switch over
order may be stored in a non-volatile memory register or media
store.
[0011] Referring now to FIG. 1, the figure depicts a schematic view
of a configuration of an exemplary photonic integrated circuit
package 100. The photonic integrated circuit package may be
constructed as a DWDM interconnect. Solid arrows indicate an
optical connection and dashed arrows indicate an electrical
connection. The photonic integrated circuit 100 has multiple comb
laser modules 110, 111, 112, 113 114, 115 116, 118 bonded onto an
SiP interposer 104. Each of the comb laser modules are controlled
by the control ASIC 130. Each of the comb laser modules are a
single laser capable of generating multiple laser lines, typically
generating 16 and up to 32 lines, on a single optical output.
[0012] Comb laser modules 110, 111, 112 form a laser module array.
The laser module array may have n number of laser modules in the
array, for example L.sub.1a, L.sub.1b, L.sub.1c, . . . L.sub.1n. In
an operative state of the photonic integrated circuit package 100,
as further described below, the comb laser modules in the array are
operated individually, with one of the comb laser modules being
powered for operation and data transmission. The non-powered comb
laser modules act as a backup to the active comb laser module in
the array. In other words, one operative comb laser module in an
array provides data transmission, while the other comb laser
modules in the array remain unpowered.
[0013] This configuration allows use of redundant comb laser
modules. In a first array comb laser modules L.sub.1b 110 and laser
module L.sub.1c 111 provide redundancy and serve as back-up comb
laser modules for laser L.sub.1a 112. While not shown in the
figure, each comb laser module has an integrated optical power
monitor. The comb laser module's integrated optical power monitor
observes the optical output of the laser module. The control ASIC
can switch over to the back-up comb laser module in an array should
the primary laser module fail. For example, the control ASIC 130
may detect failure or the likelihood of failure of the then current
operating laser in the array 112. A redundant laser 110 in the
laser array may be initialized and powered to an operative state. A
controlled switch over from the failing operative comb laser module
to the backup comb laser module may be performed. During the
controlled switch over, the ASIC may stop data transmission by the
integrated circuit package 100. Power to the failing operative
laser module 112 is stopped, and power is provided to the backup
comb laser module 110. The control circuitry may run a preliminary
diagnostic to evaluate whether the backup comb laser module is
operating within a desired power output range. If within a desired
power input, and output range, then the control circuitry would
begin data transmission again with the backup comb laser module
110. If the first backup comb laser module 110 is determined to be
unsuitable, then the next backup laser module 111 in the array
would be used.
[0014] Switching over from one comb laser module in a particular
array to another comb laser module in the same array may be
performed in automated manner where the control circuitry performs
the switch over when a switch over event is determined, such as
detecting a failing of failed comb laser module. Additionally, the
control circuitry may receive instructions from a remote source
directing the package 104 to switch to another comb laser module.
This is especially useful where a separate service may monitor the
circuit package 100, and determine or schedule the circuit package
100 to use a different comb laser module.
[0015] Each of the comb laser modules have an effective spectral
range of emission. Each array covers a separate frequency domain.
By coupling the outputs of multiple comb laser modules from
different arrays, the circuit package may extend the overall
spectral range of emission. As shown, comb laser modules L.sub.1a
112 and L.sub.2a 114 each produce powered output in two different
spectral ranges. When these spectral ranges are combined, the
circuit package 100 increases its effective spectral range via
optical coupler 120. This makes the two comb laser modules
effectively behave as one laser with a greater spectral range. An
additional number of n comb laser modules with different frequency
domains may be coupled together thereby increase the overall
frequency range of the circuit package 100, and the number of
possible or usable channels.
[0016] The comb laser modules have a spectral range bandwidth of
emission of between 7 nm to 11 nm. Combining the spectral bandwidth
of two arrays, the circuit package 100 may obtain an effective
bandwidth of 14 nm to 22 nm. In one configuration, each of the comb
laser modules have about an 8-10 nm spectral bandwidth. To cover
transmission over the O-band (1280-1360 m) with a range of about
100 nm, 10 arrays of comb laser modules may be used. The circuit
package 100 would combine each of the comb laser modules output to
cover the 0-band range. Each array would include two or more comb
laser modules in the array. With a configuration of 10 separate
arrays and 3 comb laser modules per array, the circuit package 100
would include 30 total comb laser modules coupled to the SiP
interposer 104.
[0017] Comb laser module 114 and the laser modules in the Li array
110, 112 are each optically coupled to the optical coupler 120. The
optical coupler 120 may be an on-chip optical coupler with n number
of optical inputs, with typically one output. The optical coupler
120 is electrically controlled via the control ASIC 130. The
control ASIC may be one more CMOS chips that handle logic
processing and electrical input/output to control and interface
with the comb laser modules 110, 111, 112, 113, 114, 115, 116, 118,
the optical coupler 120, the optical power monitor 140 and the
communications port 160. The optical coupler 120 is a multi-port
Kx1 coupler that provides many optical inputs to one optical
output. The control ASIC controls the phase between the optical
inputs to obtain a low loss output.
[0018] The optical coupler 120 has integrated feedback components
to allow the coupler to be tuned for the correct optical coupling
ratio between its various inputs. The optical coupler 120 is
optically coupled to the fiber array 150. The fiber array 150 is a
2-dimensional array of optical output ports to be addressed by a
fiber array that allows M.times.N connections.
[0019] Comb laser module 116 is optically coupled to fiber arrays
152, 154. An optical power monitor 140 is optically coupled to the
comb laser module 116. The optical power monitor 140 may be an
integrated photodiode within the SiP interposer 104, and may
monitor the optical power output from a laser. By using feedback
from the on-chip optical power monitor 140, the control ASIC 130
may ensure proper bias on the laser to maintain the required
optical signal out of the comb laser module and can adjust the bias
as necessary.
[0020] While not depicted in FIG. 1, each of the comb laser modules
110, 111 112, 113, 114, 115, 116, 118 may each have a coupled
optical power monitor allowing monitoring of the optical power
output from the respective comb laser modules. All of the other
comb laser modules are implied to have such an optical power
monitor, but are not drawn for simplicity.
[0021] The SiP interposer 104 may have attached thereon n comb
laser modules 118, or n arrays of comb laser modules, or a
combination thereof. The Ln laser module 118 is optically coupled
to the fiber arrays 152,154. By using efficient couplers on the SiP
interposer 104, the single output of a comb laser module may be
separated among multiple outputs and routed to various fiber ports.
This is shown by laser L.sub.n 118 where its output is coupled to
one of the input of the fiber arrays 152, 154.
[0022] A communications port 160 is electrically coupled to the
control ASIC 130. The electrical port refers to a standard
electrical interface, and may be a connection of a type of RS-232,
Ethernet, QSFP, or any other type that allows the circuit package
100 to electrically communicate with another system, or other
devices. By using out-of-band communication either electrical or
optical, the circuit package 100 may communicate with other
components such as optical transmitters, compute nodes, switches,
etc.
[0023] Referring now to FIG. 2, the figure depicts a schematic view
of the configuration of an exemplary photonic integrated circuit
package 200. The photonic integrated circuit package 200 may be
constructed as a DWDM interconnect. One comb laser module in each
array is used during operation of the circuit package 200. The
other comb laser modules in the array serve as redundant, or
back-up, comb laser modules in the array. The control circuitry
monitors each of the operative comb laser modules, and can
determine the actual or likely failure of a comb laser modules.
Moreover, the control circuitry may periodically switch between use
of any comb laser module in an array.
[0024] This configuration depicts three arrays of comb laser
modules. Array one includes comb laser modules 210, 212, 214. Array
two includes comb laser modules 220, 22, 224. And array three
includes comb laser modules 230, 232, 234. While each array
includes three comb laser modules, each array can be configured
with any number of comb laser modules in the array. For redundancy
purposes the array would include at least two comb laser modules in
the array. The comb laser modules are bonded to a substrate 250,
such as a silicon interposer.
[0025] While three arrays are show in this example, n number of
arrays may be used. The number of arrays will be based on the
overall bandwidth and the number of channels needed for the
particular application.
[0026] Each of the comb laser module in the array have a similar
spectral emission range. The spectral range of the comb laser
modules in array one is different than the spectral range of
emission of array two, and different from that of array three. Each
array is meant to provide a particular spectral range, and each
comb laser module serve as a backup to the other comb laser modules
in the array.
[0027] Each of the comb laser modules in an array are optically
coupled to a local waveguide. For example, comb laser modules 210,
212, 214 are optically coupled to local waveguide 216. Comb laser
modules 220, 222, 224 are optically coupled to local waveguide 226.
Comb laser modules 230, 232, 234 are optically coupled to local
waveguide 236. The waveguides 216, 226, 236 are disposed within a
substrate, such as silicon or other semiconductor based
material.
[0028] Each of the waveguides 216, 226, 236 are optically coupled
to an optical coupler 260. The optical coupler is optically coupled
to an MxN fiber array 270.
[0029] Control circuitry 240 control various components of the
photonic integrated circuit package 200. Dotted lines depicted an
electrical connection between components. The control circuitry
depicted in the diagram is in the form of an ASIC. The ASIC
determines which comb laser modules in an array are provided. The
ASIC also controls data communication, data transmission and other
operations.
[0030] An optical power monitor is coupled to each comb laser
module. For simplicity, only optical power monitor 280 is shown is
shown in the figure. The optical power monitor 280 monitors emitted
wavelength from comb laser module 210 via the local waveguide 218.
The control circuitry 240 can determine whether the power output of
a laser module is within an expected range based on the power
input.
[0031] A communications port 290 is electrically coupled to the
control ASIC 240. The electrical port refers to a standard
electrical interface, and may be a connection of a type of RS-232,
Ethernet, QSFP, or any other type that allows the circuit package
200 to electrically communicate with another system, or other
devices. By using out-of-band communication either electrical or
optical, the circuit package 200 may communicate with other
components such as optical transmitters, compute nodes, switches,
etc.
[0032] Referring now to FIG. 3, an exemplary process for the
control and operation of the circuit package shown. The control
circuitry of the circuit package provides for monitoring the health
of an operating laser, and may automatically switch over to a
redundant laser in a laser array for back-up due to a failed or
failing comb laser module. The control circuitry, a separate
processor, and/or other firmware may be used for control and/or
monitoring of the comb laser modules in an array.
[0033] The process begins 310 and the control circuitry provides
power to a first comb laser module in a first array 320, and
provides power to a first comb laser module in a second array 330.
The control circuitry may monitor the optical output power and the
current of an operative comb laser module 330. The control
circuitry determines whether a switch over event for one of the
comb laser modules has occurred 340 and/or should occur for the
operative comb laser module in the array. The control circuitry may
determine that a switch over event has occurred 350. For example,
the control circuitry may determine that the first comb laser
module of the first array has a higher than threshold level of
power input to achieve a set power output.
[0034] The control circuitry then ceases data transmission using
the first comb laser module 360. The control circuitry selects
another comb laser module in the array for continued operation 370.
The selected comb laser module is then powered on, and the control
circuitry resumes data transmission using the selected comb laser
module 380. The first comb laser module may be identified as
inoperative, and disabled from subsequent use by the circuit
package.
[0035] During this controlled switch over, the control ASIC may
adjust the laser bias to maintain required optical power, and
optionally perform dynamic routing of the laser output to various
inputs for adjustment of overall number of channels.
[0036] Optionally, an initial evaluation may be performed for each
comb laser module in an array. The control circuitry may determine
the operative characteristics of each comb laser. For example,
assuming an array of three comb laser modules (L.sub.1a, L.sub.1b,
L.sub.1c), the control circuitry may evaluate the power output of
each comb laser module in the array based on a given power input.
This information may be stored in a non-volatile memory register as
a hash-table for example for later use. The hash-table may include
identifiers for each the comb laser modules in an array, and other
information designating a preferred order of use. During this
evaluation, it may be found that laser L.sub.1c is the most
efficient laser, then L.sub.1b, and lastly laser L.sub.1a. The
control circuitry may then designate a preferred order of use of
the comb laser modules in the array, for example L.sub.1c, L.sub.1b
and L.sub.1a. After this initial evaluation process has been
performed, the control circuitry may selectively use laser L.sub.1c
as the default for the primary operative laser.
[0037] In certain cases, the initial evaluation process may
determine that one of the comb laser modules is defective, or not
suitable for use. In this instance, the particular laser will be
identified for non-use, and will not act as a backup laser module
in the event of failure of another of the comb laser modules in the
array.
[0038] This evaluation process may be periodically performed. Over
time, constant use of a comb laser module may subject a comb laser
module to thermal fluctuations which may cause the operating
characteristics of the comb laser module to change over time. The
required power to achieve a desired output of a primary operative
laser module may increase over time. The evaluation process may
determine that a comb laser module initially identified as the
preferred laser module for use, may now in fact, be less desirable
for use than one of the other laser modules in the array.
Continuing the example with the three comb laser modules (L.sub.1a,
L.sub.1b, L.sub.1c), while initially comb laser module Li.sub.1c
was identified as the primary operative laser, it may be determined
that now comb laser module L.sub.1b is now the preferred laser for
use as the primary operative laser. In this case, the control
circuitry, after performing the evaluation process, will designate
comb laser module L.sub.1b as the primary operative laser. Should
comb laser module L.sub.1b fail during normal operation, the
control circuitry may select between the remaining comb laser
modules in the array for continued normal operation.
[0039] The foregoing description, for purposes of explanation, used
specific nomenclature to provide a thorough understanding of the
disclosure. However, it will be apparent to one skilled in the art
that the specific details are not required in order to practice the
systems and methods described herein. The foregoing descriptions of
specific examples are presented for purposes of illustration and
description. They are not intended to be exhaustive of or to limit
this disclosure to the precise forms described. Obviously, many
modifications and variations are possible in view of the above
teachings. The examples are shown and described in order to best
explain the principles of this disclosure and practical
applications, to thereby enable others skilled in the art to best
utilize this disclosure and various examples with various
modifications as are suited to the particular use contemplated. It
is intended that the scope of this disclosure be defined by the
claims and their equivalents below.
* * * * *