U.S. patent application number 10/307104 was filed with the patent office on 2004-05-27 for method and apparatus for controlling an optical transponder.
Invention is credited to Crosby, Philip S., Icaza, Alejandro E..
Application Number | 20040102874 10/307104 |
Document ID | / |
Family ID | 32325827 |
Filed Date | 2004-05-27 |
United States Patent
Application |
20040102874 |
Kind Code |
A1 |
Crosby, Philip S. ; et
al. |
May 27, 2004 |
Method and apparatus for controlling an optical transponder
Abstract
Methods and apparatus are provided in accordance with the
present invention in which a control mechanism, such as for
example, a microcontroller, provides an interface between an
optical transponder and an external control system, such that
monitoring and controlling of the optical components of the optical
transponder are accomplished in an efficient and cost-effective
manner. In some embodiments of the present invention, methods and
apparatus provide for testing and calibration of the optical
transponder without removing any portion of a protective housing
within which the internal components of the optical transponder are
disposed.
Inventors: |
Crosby, Philip S.;
(Portland, OR) ; Icaza, Alejandro E.; (Beaverton,
OR) |
Correspondence
Address: |
SCHWABE, WILLIAMSON & WYATT, P.C.
PACWEST CENTER, SUITES 1600-1900
1211 SW FIFTH AVENUE
PORTLAND
OR
97204
US
|
Family ID: |
32325827 |
Appl. No.: |
10/307104 |
Filed: |
November 27, 2002 |
Current U.S.
Class: |
700/299 |
Current CPC
Class: |
H04B 10/672
20130101 |
Class at
Publication: |
700/299 |
International
Class: |
G05D 023/00 |
Claims
What is claimed is:
1. A method of monitoring and controlling an optical transponder
module, comprising: executing a software program, stored in a
memory disposed within the optical transponder module, on a
microcontroller disposed within the optical transponder module;
sensing characteristics of the optical transponder module; and
communicating information indicative of the sensed characteristics
to one or more output terminals of the optical transponder module;
wherein the optical transponder module includes a case.
2. The method of claim 1, wherein sensing characteristics comprises
sensing the temperature at one or more locations within the optical
transponder module.
3. The method of claim 1, wherein sensing characteristics comprises
sensing the temperature at one or more locations within the optical
transponder module, sensing receive power, and sensing transmitter
power.
4. The method of claim 3, wherein sensing the temperature comprises
converting an analog signal representative of the temperature to a
digital value and providing that digital value to the
microcontroller, sensing receive power comprises converting an
analog signal representative of receive power to a digital value
and providing that digital value to the microcontroller, and
sensing transmit power comprises converting an analog signal
representative of transmitter power to a digital value and
providing that digital value to the microcontroller.
5. The method of claim 1, wherein executing the software program
comprises generating a plurality of digital values , converting the
digital values to analog control signals and communicating the
analog control signals to one or more opto-electronic circuits
within the optical transponder module.
6. The method of claim 1, wherein the case comprises a physically
protective and thermally conductive case.
7. An optical transponder, comprising: a plurality of electrical
and optical components disposed within a housing, the housing being
adapted to be physically protective of the optical components, and
further being adapted to conduct heat, at least while the optical
transponder is in operation, away from the optical components; a
microcontroller, disposed within the housing, the microcontroller
adapted to communicatively interface with a controller external to
the housing; a temperature sensor electrically coupled to the
microcontroller; a parameter memory, coupled to the
microcontroller, adapted to store calibration information; and a
connector, disposed through the housing, adapted to provide
electrical communication pathways between the electrical components
and at least one device external to the housing, and to further
provide electrical communication pathways between the
microcontroller and at least one device external to the
housing.
8. The optical transponder of claim 7, wherein the electrical
components comprise a parallel-to-serial converter adapted to
receive a plurality of signal inputs and provide a serial bit
stream at an output terminal; and a serial-to-parallel converter
adapted to receive a serial bit stream at an input terminal and to
provide a plurality of signal outputs.
9. The optical transponder of claim 8, wherein the optical
components comprise a laser adapted to provide an optical output
signal; and a photodiode adapted to receive an optical input
signal.
10. The optical transponder of claim 9, wherein the temperature
sensor comprises a thermistor.
11. The optical transponder of claim 7, further comprising a
programmable, non-volatile, program code memory disposed within the
housing, and coupled to the microcontroller.
12. The optical transponder of claim 7 further comprising: an A/D
converter electrically coupled between the microcontroller and one
or more of the plurality of electrical and optical components.
13. An optical transponder, comprising: a parallel-to-serial
converter adapted to receive a first plurality of electrical
signals and having at least one output terminal; an
electrical-to-optical converter having an input terminal coupled to
the output terminal of the parallel-to-serial converter, and having
an output terminal adapted to provide at least one optical signal;
an optical-to-electrical converter having an input terminal adapted
to receive at least one optical signal, and having an output
terminal adapted to provide an electrical signal; a
serial-to-parallel converter having an input terminal coupled to
the output terminal of the optical-to-electrical converter, and
having a plurality of output terminals adapted to provide a second
plurality of electrical signals; a microcontroller; at least one
temperature sensor electrically coupled to the microcontroller; and
a parameter memory coupled to the microcontroller; wherein the
parallel-to-serial converter, the electrical-to-optical converter,
the optical-to-electrical converter, the serial-to-parallel
converter, the microcontroller, the at least one temperature
sensor, and the parameter memory are all disposed within a
case.
14. The optical transponder of claim 13, further comprising: a D/A
converter having a plurality of digital input terminals coupled to
the microcontroller, and having a plurality of analog output
terminals, at least a first one of the analog output terminals
being coupled to the electrical-to-optical converter; and an A/D
converter having a plurality of analog input terminals, and a
plurality of digital output terminals coupled to the
microcontroller; wherein the D/A converter and the A/D converter
are disposed within the case.
15. The optical transponder of claim 14, wherein the
electrical-to-optical converter is coupled to at least one of the
plurality of the A/D converter analog input terminals.
16. The optical transponder of claim 14, wherein the
optical-to-electrical converter is coupled to at least one of the
plurality of the A/D converter analog input terminals.
17. The optical transponder of claim 14, wherein the
electrical-to-optical converter is coupled to at least one of the
plurality of the A/D converter analog input terminals; the
optical-to-electrical converter is coupled to at least one of the
plurality of the A/D converter analog input terminals; and the at
least one temperature sensor comprises at least one thermistor.
18. The optical transponder of claim 17, further comprising a
program code memory coupled to the microcontroller.
19. The optical transponder of claim 14, wherein at least a second
one of the plurality of D/A converter analog output terminals is
coupled to the optical-to-electrical converter.
20. The optical transponder of claim 13, further comprising an
electrical connector coupled to the case, and adapted to provide a
plurality of input, output, and bi-directional electrical signal
paths between the microcontroller and at least one device external
to the case.
21. A method of operating an optical transponder module,
comprising: receiving a first signal indicative of a temperature in
at least one region within a case of the optical transponder
module; accessing parameter information stored in a first memory,
the first memory being disposed within the case; and determining,
based at least in part, on the first signal and the parameter
information, a desired control signal.
22. The method of claim 21 wherein the desired control signal
comprises a digital value which, when applied to a D/A converter
will produce a desired analog signal.
23. The method of claim 21, further comprising applying the desired
control signal to an opto-electronic circuit within the case.
24. The method of claim 23, wherein the opto-electronic circuit
comprises an electrical-to-optical converter.
25. The method of claim 23, wherein the opto-electronic circuit
comprises an optical-to-electrical converter.
26. The method of claim 21, wherein determining the desired control
signal comprises executing stored instructions by a microcontroller
which is disposed within the case.
27. The method of claim 26, further comprising storing instructions
for execution by the microcontroller, into a memory within the
optical transponder module, from a device external to the optical
transponder module.
28. A method of monitoring a set of operational characteristics of
an optical transponder module, comprising: developing a plurality
of characteristic signals, each of the characteristic signals
representative of at least one operational characteristic in the
set of operational characteristics; processing the plurality of
characteristic signals within a microcontroller by executing stored
instructions, the microcontroller being disposed within the optical
transponder module, whereby operational status information,
representative of one or more of the operational characteristics is
generated; and providing the operational status information to
output terminals that are coupled to the microcontroller, and that
are adapted to couple with devices external to the optical
transponder module.
29. The method of claim 28, wherein one of the characteristic
signals is representative of at least one of temperature, receive
power, and transmit power.
30. The method of claim 28, wherein the set of operational
characteristics comprises at least one of temperature, receive
power, and transmitter power.
31. The method of claim 28, wherein the devices external to the
optical transponder module comprise electronic devices, and the
output terminals are adapted to provide electrical signals
thereon.
32. The method of claim 28, further comprising determining whether
at least one of the operational characteristics is outside of a
normal operating range, and if such determination is affirmative,
then communicating an alarm signal.
33. The method of claim 32, wherein the alarm signal comprises
information communicated through the output terminals coupled to
the microcontroller.
34. A method of operating an optical transponder, comprising:
reading one or more calibration values from a memory; generating a
control signal based, at least in part, on at least one of the
calibration values; and providing the control signal to an input
terminal of an electrical-to-optical converter; wherein the
performance of the electrical-to-optical converter is controlled,
at least in part, by the control signal.
35. The method of claim 34 wherein generating the control signal
comprises: providing a digital value to a D/A converter, the
digital value based, at least in part, on at least one of the
calibration values read from the memory; and generating an analog
signal at an output terminal of the D/A converter.
36. The method of claim 35, further comprising providing a second
digital value to the D/A converter, the second digital value based,
at least in part, on at least one of the calibration values read
from the memory; generating a second analog signal at a second
output terminal of the D/A converter; and providing the second
analog signal to an input terminal of an optical-to-electrical
converter; wherein the performance of the optical-to-electrical
converter is controlled, at least in part, by the second analog
signal.
37. The method of claim 35, further comprising providing a second
digital value to the D/A converter, the second digital value based,
at least in part, on at least one of the calibration values read
from the memory; generating a second analog signal at the output
terminal of the D/A converter; and providing the second analog
signal to an input terminal of an optical-to-electrical converter;
wherein the performance of the optical-to-electrical converter is
controlled, at least in part, by the second analog signal.
38. The method of claim 34, wherein the calibration values are
digital values; the first memory is a programmable, non-volatile
memory disposed within a case that provides physical protection and
thermal dissipation for the optical transponder; reading comprises
accessing the first memory by applying control signals to the first
memory, the control signals generated by a microcontroller disposed
within the case.
39. The method of claim 34, wherein providing the control signal
comprises providing a digital value on one or more output terminals
of a microcontroller disposed within a case that provides physical
protection and thermal dissipation for the optical transponder.
40. The method of claim 34, wherein the memory and a
microcontroller are integrated on a single chip, and the single
chip is disposed within a case that provides physical protection
and thermal dissipation for the optical transponder
41. A method of monitoring and recording operational status
information regarding the performance of an optical transponder
module, comprising: developing a plurality of characteristic
signals, each of the characteristic signals representative of at
least one operational characteristic; processing the plurality of
characteristic signal within a microcontroller by executing stored
instructions, the microcontroller being disposed within the optical
transponder module, whereby operational status information,
representative of one or more of the operational characteristics is
generated; and storing the operational status information in a
memory disposed within the optical transponder.
42. The method of claim 41, wherein the memory is a non-volatile
memory.
43. The method of claim 41, wherein the memory is integrated on a
single chip with the microcontroller.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates generally to computer-based
industrial control systems, such as microprocessor control of
analog and digital functionality, and more particularly relates to
methods and apparatus for calibrating, monitoring, and controlling
optical transponders.
[0003] 2. Background Information
[0004] With advances in integrated circuit, microprocessor,
networking and communication technologies, an increasing number of
devices, in particular, digital computing devices, are being
networked together. Such devices are often first coupled to a local
area network, such as an Ethernet-based office/home network. In
turn, the local area networks are interconnected together through
wide area networks, such as Synchronous Optical Networks (SONET),
Asynchronous Transfer Mode (ATM) networks, Frame Relays, and the
like. Of particular importance is the TCP/IP based global
inter-network, the Internet. The rapid growth of the Internet has
fueled a convergence of data communication (datacom) and
telecommunication (telecom) protocols and requirements. It is
increasingly important that data traffic be carried efficiently
across local, regional and wide area networks.
[0005] As a result of this trend of increased connectivity, an
increasing number of applications that are network dependent are
being deployed. Examples of these network dependent applications
include, but are not limited to, the World Wide Web, email,
Internet-based telephony, and various types of e-commerce and
enterprise applications. The success of many content/service
providers as well as commerce sites depends on high-speed delivery
of a large volume of data across wide areas. In turn, this trend
leads to an increased demand for high-speed data trafficking
equipment, such as high-speed optical-electrical routers or
switches and the like. In other words, as a widening variety of new
and traditional services converge across shared inter-networking
transport structures, there is a critical need for the Internet to
simultaneously deliver higher bandwidths, more reliable service,
and greater deployment flexibility.
[0006] The widespread deployment of high-speed networking and
communications equipment has produced a large demand for various
types of networking and communications components and subsystems.
Included among these are modules often referred to as optical
transponders.
[0007] Optical transponders typically include components for both
electrical signal processing, and components for transmission and
reception of optical signals. Conventional optical transponders
typically receive electrical signals in parallel, serialize the
data represented by these signals, convert the serialized data into
a light-based signal and couple that signal to an outbound optical
fiber. Similarly, conventional optical transponders, typically
receive a serialized light-based data stream, convert that data
stream to an electrical equivalent, de-serialize that data, and
provide the de-serialized electrical data, i.e., data in a parallel
format, to a plurality of output terminals. Conventional optical
transponders typically include a case, or housing, within which the
electrical and optical components are housed. Such a case provides
physical protection for the components, and also provides thermal
conductivity so that heat may be dissipated from the components
disposed within the case.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Examples of the present invention are illustrated in the
accompanying drawings. The accompanying drawings, however, do not
limit the scope of the present invention. Similar references in the
drawings indicate similar elements.
[0009] FIG. 1 is a high-level block diagram showing an optical
transponder having a parallel-to-serial converter coupled to an
electrical-to-optical converter, and an optical-to-electrical
converter coupled to a serial-to-parallel converter, all housed in
a physically protective and thermally conductive case, in
accordance with the prior art.
[0010] FIG. 2 is a block diagram showing an optical transponder
having a parallel-to-serial converter coupled to an
electrical-to-optical converter, an optical-to-electrical converter
coupled to a serial-to-parallel converter, a microcontroller,
having a program memory, coupled to a parameter memory, an
analog-to-digital (A/D) converter, a digital-to-analog (D/A)
converter, and a temperature sensor coupled to the A/D converter,
all housed in a physically protective and thermally conductive
case, in accordance with the present invention.
[0011] FIG. 3 is a flow chart illustrating a method of controlling
the operation of at least one opto-electronic component disposed in
an optical transponder module in accordance with the present
invention.
[0012] FIG. 4 is a flow chart illustrating a method of monitoring
the operation of at least one opto-electronic component disposed in
an optical transponder module, and recording information based the
monitored operation in accordance with the present invention.
[0013] FIG. 5 is a flow chart illustrating a method of monitoring
the operation of at least one opto-electronic component disposed in
an optical transponder module, and reporting information to a
device external to the optical transponder based on the monitored
operation in accordance with the present invention.
[0014] FIG. 6 is a flow chart illustrating a method of monitoring
and controlling the operation of at least one opto-electronic
component disposed in an optical transponder module in accordance
with the present invention.
[0015] FIG. 7 is a flow chart illustrating a method of calibrating
the operation of at least one opto-electronic component disposed in
an optical transponder module in accordance with the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0016] Embodiments of the present invention calibrate, monitor, and
control the components disposed within the case of an optical
transponder module. For example, in one embodiment, a
microcontroller inside an optical transponder provides an interface
between the optical transponder and an external system to
calibrate, monitor, and control the components of the optical
transponder in an efficient and cost-effective manner. Some
embodiments of the present invention calibrate, monitor, and
control the optical transponder with a protective housing for the
internal components of the optical transponder in place.
[0017] In the following description, various aspects of the present
invention will be described. However, it will be apparent to those
skilled in the art that the present invention may be practiced with
only some or all aspects of the present invention. For purposes of
explanation, specific numbers, materials and configurations are set
forth in order to provide a thorough understanding of the present
invention. However, it will also be apparent to one skilled in the
art that the present invention may be practiced without the
specific details. In other instances, well-known features are
omitted or simplified in order not to obscure the present
invention.
[0018] Reference herein to "one embodiment", "an embodiment", or
similar formulations, means that a particular feature, structure,
or characteristic described in connection with the embodiment, is
included in at least one embodiment of the present invention. Thus,
the appearances of such phrases or formulations herein are not
necessarily all referring to the same embodiment. Furthermore,
various particular features, structures, or characteristics may be
combined in any suitable manner in one or more embodiments.
[0019] The term, microcontroller, generally refers to a class of
integrated circuits, that includes, typically within a single chip,
components such as, but not limited to, a central processing unit
(CPU), a random access memory (RAM), a non-volatile memory, such
as, but not limited to, a read only memory (ROM), that stores
program code for execution by the CPU, a variety of input, output,
input/output terminals (collectively referred to as ports), and may
often include timer or counter circuits. Microcontrollers are
sometimes referred to as embedded controllers, because they are
part of an embedded system. Single-chip microcontrollers of a wide
variety of architectures and specifications are commonly available
from a broad range of manufacturers, and can be considered as a
commodity item. As used herein, microcontroller refers to the
definition above, as well as any other single-chip or multi-chip
implementation of the logic required to provide the functionality
described in connection with the various embodiments of the present
invention.
[0020] The terms chip, integrated circuit, monolithic device,
semiconductor device or component, and microelectronic device or
component, are often used interchangeably in this field. The
present invention is applicable to all of the above as they are
generally understood in the field.
[0021] FIG. 1 is a high-level block diagram showing an optical
transponder module 100 having a parallel-to-serial converter
coupled to an electrical-to-optical converter, and an
optical-to-electrical converter coupled to a serial-to-parallel
converter, all housed in a physically protective and thermally
conductive case, in accordance with the prior art. More
particularly, a case 102 has disposed therein a parallel-to-serial
converter 104, coupled to an electrical-to-optical converter 106,
by way of a communications path 108. Communications path 108 is
typically formed of an electrically conductive material disposed on
an insulating substrate. Such an arrangement is typical of printed
circuit boards. Parallel-to-serial converter 104 is adapted to
receive electrical inputs at a plurality of input terminals which
are coupled to electrical input communications path 110.
Communications path 110 typically consists of a plurality of
low-voltage swing differential signal line pairs.
Electrical-to-optical converter 106 converts the serialized
electrical data into modulated laser light which is then coupled
onto optical output 112. Case 102 further has disposed therein, an
optical-to-electrical converter 114, that is coupled to a
serial-to-parallel converter 116. A communications path 118,
typically consisting of electrically conductive material disposed
on an insulating substrate, is used to transfer serial data, in
electrical format, between optical-to-electrical converter 114, and
serial-to-parallel converter 116. The output terminals of
serial-to-parallel converter 116 are coupled to communications path
122. Communications path 122 typically consists of a plurality of
low-voltage swing differential signal line pairs. Case 102 serves
to provide both physical protection for the components of optical
transponder module 100 and a thermally conductive pathway for
removing waste heat from the various active components of optical
transponder module 100.
[0022] Conventional optical transponders, such as the one
illustrated in the high-level block diagram of FIG. 1, often employ
control means such as jumpers, mechanical switches, and
potentiometers to establish the digital and analog parameters
necessary for the proper and correct functioning of those optical
transponders, or similar modules. In order to conventionally make
these adjustments, the optical transponder must have its outer case
removed. Since this case serves to perform both a physically
protective and a thermally dissipative function, these adjustments
must be performed when the optical transponder is not in its
intended configuration, thereby often leading to inaccurate
calibration. Furthermore, reconfiguration of an optical transponder
conventionally necessitates at least partial disassembly of the
unit.
[0023] Conventional optical transponder interface standards, or
specifications, require separate dedicated pins on the interface
connector for the digital and analog control and monitoring
functions. The functionality of such modules cannot easily be
enhanced or modified unless general agreement within the industry
can be established with respect to the function of the one or more
connector pins that might be affected by a desired enhancement or
modification. This inflexible architecture tends to increase the
size, expense, and complexity of the interface connector and
constitutes a significant barrier to innovations that could improve
the functionality, reliability, and appropriateness for a
particular purpose, of an optical transponder module.
[0024] Embodiments of the present invention provide methods and
apparatus to achieve the monitoring and controlling of optical
transponder modules and/or the components disposed within the case
of an optical transponder module, including, in some embodiments,
providing an interface to an external control module or other type
of control system. In some embodiments, the functionality to
support the above-mentioned monitoring and controlling is provided,
at least in part, by computational resources such as, for example,
microprocessors or microcontrollers that are included along with
the other electronic component of the optical transponder module.
Such microprocessors or microcontrollers are sometimes referred to
as being embedded.
[0025] In some embodiments of the present invention, registered
control bits are employed to perform the functions conventionally
performed by means such as the jumpers and switches mentioned
above. Such control bits may be incorporated within a
microcontroller included within the optical transponder, or may be
implemented with logic components outside of a microcontroller, but
coupled thereto. The functionality of the conventional
potentiometers, in some embodiments of the present invention, is
performed by digital-to-analog converters (DACs). Further, in some
embodiments, analog-to-digital converters (ADCs) are used variously
to perform monitoring and closed-loop control functions.
[0026] In some embodiments, the control program and/or control
parameters for a microcontroller in the optical transponder module
can be electrically loaded using either an additional control
interface, or through the aforementioned control interface, which
may require using a multiplexer or other architecturally suitable
means to separate the program code from the control and monitoring
signals. It is noted that in some embodiments the control program
and/or control parameters can be re-loaded, thereby providing for a
repair, and/or modification process, in which corrected or updated
program code can be provided to the program code memory of the
microcontroller (which includes any other suitable stored program
architecture device or devices, as that term is used herein). In
such embodiments, any suitable type of non-volatile memory may be
used, such as, but not limited to, flash memory, electrically
erasable/programmable memory (EEPROM), fuse or anti-fuse arrays,
phase change material memories, battery-backed volatile memories,
and so on. In still other embodiments, the control program for the
microcontroller is stored in Read Only Memory (ROM) that is either
integrated on a single chip with the microcontroller, or located
external to the microcontroller but coupled thereto.
[0027] An architecture, in accordance with the present invention,
provides for monitoring and controlling optical transponder modules
without removing the physically protective and thermally conductive
housing (i.e., case), which in turn allows for one or more of the
manufacture, calibration, testing, maintenance, and operation of an
optical transponder module in its complete form with the module
case installed and the thermally conductive paths from the critical
components in place. Since the optical transponder module is
configured, calibrated, and monitored by signals communicated
through the interface of the present invention, automated testing
and calibration procedures, also in accordance with the present
invention, are advantageously made available by such
embodiments.
[0028] FIG. 2 is a block diagram showing an optical transponder
module 200 having a parallel-to-serial converter coupled to an
electrical-to-optical converter; an optical-to-electrical converter
coupled to a serial-to-parallel converter; a microcontroller,
having a program memory, coupled to a parameter memory; an
analog-to-digital (A/D) converter coupled to the microcontroller; a
digital-to-analog (D/A) converter coupled to the microcontroller;
and a temperature sensor coupled to the A/D converter; all housed
in a physically protective and thermally conductive case, in
accordance with the present invention. More particularly, a case
202 has disposed therein a parallel-to-serial converter 104,
coupled to an electrical-to-optical converter 106, by way of a
communications path 108. Communications path 108 is typically
formed of an electrically conductive material disposed on an
insulating substrate. Parallel-to-serial converter 104 is adapted
to receive electrical inputs at a plurality of input terminals
which are coupled to electrical input communications path 110.
Communications path 110 typically consists of a plurality of
low-voltage swing differential signal line pairs.
Electrical-to-optical converter 106 converts the serialized
electrical data into modulated laser light which is then coupled
onto optical output 112. Case 202 further has disposed therein, an
optical-to-electrical converter 114, that is coupled to a
serial-to-parallel converter 116. A communications path 118,
typically consisting of electrically conductive material disposed
on an insulating substrate, is used to transfer serial data, in
electrical format, between optical-to-electrical converter 114, and
serial-to-parallel converter 116. The output terminals of
serial-to-parallel converter 116 are coupled to communications path
122. Communications path 122 typically consists of a plurality of
low-voltage swing differential signal line pairs. Case 202 serves
to provide both physical protection of the components of optical
transponder module 200 and a thermally conductive pathway for
removing waste heat from the various active components of optical
transponder module 200. In this illustrative embodiment of the
present invention, case 202 further has disposed therein, a
microcontroller 204, and a program code memory 205 coupled to
microcontroller 204. Microcontroller 204 may be any suitable device
that provides the computational resources minimally required for
any particular embodiment of the present invention. That is,
embodiments in which more functionality is required by the
designer, or in which more functionality per unit time is required,
may use more powerful microcontrollers or other logic devices
capable of providing the desired performance level. In this
illustrative example, an eight-bit RISC-type microcontroller is
used. In addition to providing the required computational
resources, microcontroller 204 provides a plurality of terminals,
which may be input terminals, output terminals, or bi-directional
(i.e., I/O) terminals. In this field, such terminals of a
microcontroller are often referred to as ports. Program code memory
205 may be integrated on the same chip on which microcontroller 204
is fabricated, or it may be a separate chip or chips. Program code
memory 205 may be any suitable type of memory as noted in more
detail above, however in the illustrative embodiment of FIG. 2,
this memory is implemented as a programmable, non-volatile memory.
By using a programmable, non-volatile memory as program code memory
205, embodiments of the present invention advantageously enable the
updating or complete replacement of the stored instructions and/or
data that control the operation of microcontroller 204, and thereby
affect the operations of optical transponder module 200.
[0029] Still referring to FIG. 2, a connector 206 is built into
case 202 and the terminals of connector 206 are electrically
coupled to microcontroller 204. Connector 206 provides an
input/output (I/O) pathway for communicating signals between
microcontroller 204 and devices or systems external to optical
transponder module 200. Other signal pathways, such as those of
communication pathway 110 and communication pathway 122, may be
bundled with connector 206, or in alternative embodiments may be
made through a separate connector that is built into case 202. A
parameter memory 208 is disposed within case 202 and coupled to
microcontroller 204. Parameter memory 208 may be any suitable form
of data storage device, but in the illustrative example of FIG. 2,
it is implemented as a programmable, non-volatile memory such as
flash memory or EEPROM. An A/D converter 210, having input
terminals adapted to receive analog signals, and output terminals
adapted to provide digital signals, is disposed within case 202.
The digital output terminals of A/D converter 210 are coupled
respectively to input terminals of microcontroller 204 by
electrical pathway 211. In the illustrative embodiment of FIG. 2,
A/D converter 210 is coupled by electrical pathways 216, 217, an
218, respectively to optical-to-electrical converter 114,
electrical-to-optical converter 106, and temperature sensor 220.
Temperature sensor 220 may be implemented with any suitable
component or components, such as for example, a thermistor
configured to develop a voltage or current signal that is
representative of the temperature in the region of optical
transponder 200 in which the thermistor is located. In some
embodiments, the A/D functionality is incorporated within a
microcontroller.
[0030] By converting one or more analog signals representative of
various operational characteristics of optical transponder module
200 to digital format, microcontroller 204, or any other digital
logic network may easily process the information, make decisions
affecting performance, communicate status information to devices
external to optical transponder module 200, store the status
information for later review or retrieval, or any such combination
of activities. By way of example and not limitation, a voltage
representative of the temperature where temperature sensor 220 is
located is coupled to A/D converter 210 which in turn provides a
digital value corresponding to the temperature to microcontroller
204. Microcontroller 204 can then make a determination, by
execution of stored instructions from program memory 205, as to
whether any action is required in view of the value of the
digitized temperature data.
[0031] Still referring to FIG. 2, a D/A converter 212, having input
terminals adapted to receive digital signals, and output terminals
adapted to provide analog signals, is disposed within case 202. The
digital input terminals of A/D converter 212 are coupled
respectively to output terminals of microcontroller 204 by
electrical pathway 213. In alternative embodiments, the D/A
functionality is integrated within a microcontroller. At least a
first analog output terminal of D/A converter 212 is coupled to
optical-to-electrical converter 114 by electrical pathway 214, and
at least a second analog output terminal of D/A converter 212 is
coupled to electrical-to-optical converter 106 by electrical
pathway 215. By converting one or more digital values to analog
signals, various circuit control functions may be implemented. By
way of example and not limitation, control functions can be
implemented for controlling optical power output levels of
electrical-to-optical converter 114.
[0032] It is noted, with respect to the illustrative embodiment of
FIG. 2, that circuits for implementing the functionality of D/A and
A/D conversion may be integrated onto a single chip with a
microcontroller, and that such modifications are within the scope
of the present invention.
[0033] Not all signals require D/A or A/D conversion. For instance,
in FIG. 2, electrical pathways 230 and 240 carried entirely digital
control signals between microcontroller 204 and parallel-to-serial
converter 104 and serial-to-parallel converter 116,
respectively.
[0034] FIGS. 3-7 are flow charts illustrating various embodiments
of the present invention, including methods of controlling the
operation of optical transponders, monitoring the operating
conditions of optical transponders and recording information
regarding those conditions, monitoring the operating conditions of
optical transponders and reporting on those conditions, monitoring
and controlling the operations of optical transponders, and
calibrating optical transponders.
[0035] FIG. 3 is a flow chart illustrating a method of controlling
the operation of at least one opto-electronic component disposed in
an optical transponder module in accordance with the present
invention. More particularly, parameter data is read from a memory
302. This memory may be referred to as a parameter memory because
of the nature of the data stored therein, but it is noted that the
physical characteristics of the memory are not determined by the
content of the data stored therein. The electrical characteristics
of the parameter memory are described above in connection with FIG.
2. The parameter information is typically read from the parameter
memory by a microcontroller. At least one digital value is then
generated, based at least in part on the parameter data 304.
Typically the microcontroller generates the digital value(s). The
digital value(s) may be the same data that was read from the
parameter memory, or it may be a function or functions of the
parameter data. In the case where the at least one digital value is
a function of the parameter data, it will be understood that the
microcontroller may make adjustments based on its knowledge of the
present operational status of the optical transponder module, such
as for example, the temperature at a particular location within the
optical transponder module.
[0036] Still referring to FIG. 3, a control signal is generated
based, at least in part, on at least one digital value that was
previously generated 306. The control signal may be digital or
analog. Generating an analog control signal is typically
accomplished by providing at least one digital value to the digital
input terminals of an D/A converter, which in turn performs the
conversion function and provides at its analog output terminals an
analog signal. An opto-electronic component within the optical
transponder module is then operated in accordance with the control
signal, be it digital or analog 308. By way of example and not
limitation, a bias circuit that provides part of the control
network that operates a laser diode in an electrical-to-optical
component, receives an analog control signal from the D/A converter
such that the output characteristics of the laser diode are a
function of that analog control signal.
[0037] FIG. 4 is a flow chart illustrating a method of monitoring
the operation of at least one opto-electronic component disposed
in, an optical transponder module, and recording information based
on the monitored operation in accordance with the present
invention. The process described in connection with FIG. 4 may be
referred to as taking a snapshot of the operational status of the
optical transponder. More particularly, one or more of the
opto-electronic components of the optical transponder module are
operated with the physically protective and thermally dissipative
cover in place 402. A signal, representative of an operational
characteristic of at least one of the opto-electronic components,
is received 404. The signal may be analog or digital. For an analog
signal, the signal is typically converted using an A/D converter to
a digital format that may include one or more digital values 406.
The digital values, which are representative of the operational
characteristics are stored in a memory that is disposed within the
optical transponder module 408. These values can subsequently be
read out and communicated to external devices. It is noted that, in
accordance with various embodiments of the present invention,
additional information may be stored in the memory along with
digital values derived from the analog signals. For example, the
optical module may include a clock, or other time and/or date
circuit, which can be read for the purpose of time-stamping the
snapshot data.
[0038] FIG. 5 is a flow chart illustrating a method of monitoring
the operation of at least one opto-electronic component disposed in
an optical transponder module, and reporting information to a
device external to the optical transponder based on the monitored
operation in accordance with the present invention. More
particularly, one or more of the opto-electronic components of the
optical transponder module are operated with the physically
protective and thermally dissipative cover in place 502. A signal,
representative of an operational characteristic of at least one of
the opto-electronic components, is received 504. The signal may be
analog or digital. For an analog signal, the signal is typically
converted using an A/D converter to a digital format that may
include one or more digital values 506. The digital values, which
are representative of the operational characteristics, are
communicated to at least one device which is external to the
optical transponder module 508. Operational characteristics
include, but are not limited to, receive power, transmit power, and
temperature. Those skilled in the art and having the benefit of
this disclosure will recognize that other components, parameters,
or operational characteristics of an optical transponder may also
be monitored consistent with the present invention.
[0039] Still referring to FIG. 5, communication 508 of the digital
values described above, is typically achieved by means of a wired
connection between the optical transponder module and the at least
one external device, however the present invention is not limited
to wired communication. For example, in some embodiments a
radio-frequency (RF), or an infra-red (IR) link may be used in
place of a wired connection to communicate information between the
optical transponder module and external devices or systems. In
embodiments that use a wired connection between the optical
transponder and an external device, any suitable architecture or
design may be used. For example, architectures and physical
connections such as but not limited to, a serial bus or a parallel
bus may be used; single-ended or differential signaling may be
used, twisted-pair or coaxial wiring may be used, synchronous or
asynchronous signaling may be used, and so on. Those skilled in the
art and having the benefit of the present disclosure will recognize
that many wired interconnection schemes are available for
implementing the communication pathway of the present
invention.
[0040] It is noted that testing of an optical transponder may
comprise the monitoring and reporting described above in connection
with FIG. 5.
[0041] FIG. 6 is a flow chart illustrating a method of monitoring
and controlling the operation of at least one opto-electronic
component disposed in an optical transponder module in accordance
with the present invention. More particularly, a first set of
control signals for operation of an optical transponder are
generated 602. In the illustrative embodiment of FIG. 2, some of
the control signals are generated by the microcontroller providing
digital values to at least one D/A converter, and the D/A
converter(s) providing, in turn, analog control signals to an
opto-electronic component such as an optical (e.g., laser)
transmitter circuit, or an optical (e.g., photodiode) receiver
circuit. The optical transponder, including the opto-electronic
components thereof, is operated, based at least in part, on the
first set of control signals 604. The operation of the optical
transponder is monitored 606. In the embodiment of FIG. 2,
monitoring certain components of the optical transponder includes
converting an analog voltage at one or more nodes to digital values
and providing those digital values to a microcontroller disposed
within the case of the optical transponder. The microcontroller,
under control of its stored program instructions, then evaluates
the operation of the optical transponder by, among other things,
comparing laser transmit power, receive current, module
temperature, and so on, to expected operating values. Based at
least in part on the monitored operations, a second set of control
signals is generated 608. In the embodiment of FIG. 2, generating
some control signals in the second set is accomplished by the
microcontroller providing one or more digital values to one or more
D/A converters (or alternatively to one or more D/A channels of a
D/A converter). The corresponding analog output signals produced by
the D/A converters being coupled to the various components produce
changes in the operational characteristics of those components. In
other words, the optical transponder is operated, based at least in
part, on the second set of control signals 610. By way of example
and not limitation, the microcontroller may determine that the
temperature of the optical transponder is such that the bias
voltage applied to a laser transmitter should be increased, and
therefore change the digital value applied to the D/A channel that
drives the bias input node of the laser transmitter. In this way,
the optical transponder is operated and monitored, and changes are
automatically made in various control signals to compensate for
drifting operational characteristics, or for any other suitable
reason.
[0042] FIG. 7 is a flow chart illustrating a method of calibrating
the operation of at least one opto-electronic component disposed in
an optical transponder module in accordance with the present
invention. In some embodiments of the present invention, a
microcontroller and D/A converters within the optical transponder
provide control signals that are generated, based at least in part,
on a stored control program executed by the microcontroller.
However, when a number of optical transponders are manufactured,
there may be differences in the performance of each of them due to
the variances in the characteristics of individual components of
the optical transponder. FIG. 7 illustrates a calibration process
in which the optical transponder, having its physically protective
and thermally dissipative cover in place, is operated, measurements
made, and calibration parameters developed and stored in a memory
within the optical transponder. The calibration parameters are used
by the stored control program executed by the microcontroller to
fine tune the control signals to compensate for various
manufacturing differences in each unit. More particularly, a first
set of control signals is provided to components within an optical
transponder module having a protective cover in place, and the
optical transponder is operated 702. The operation of the optical
transponder is monitored 704. Monitoring may include, but is not
limited to, sensing the temperature of the optical transponder at
one or more locations, sensing the transmit power, and sensing the
receive power. Information obtained from monitoring is communicated
to a device, or devices, external to the optical modulator 706. A
set of parameter values is then generated 708. Generation of the
set of parameter values is typically performed by a device, such as
but not limited to a computer, external to the optical transponder.
Subsequently, the parameter values are stored in a memory disposed
with the optical transponder module 710. In this way, unit to unit
performance variations can be reduced, by compensating, i.e.,
changing, the values used in the generation of control signals. For
example, the optical output power levels applied to an optical
transmitter circuit can be modified from nominal to adjust for
variances in performance that typically arise from the accumulation
of manufacturing tolerances.
[0043] Thus, it can be seen from the above descriptions that
methods and apparatus for calibrating, monitoring, and controlling
optical transponders have been described.
[0044] Some advantages of various embodiments of the present
invention include the architectural flexibility to enhance or
modify the functionality of an optical transponder module without
having to define a new interface connector standard.
[0045] Another advantage of some embodiments of the present
invention include the ability to engage in automated testing of the
optical transponder module while the physically protective and
thermally conductive case, or housing, of the optical transponder
module is in place.
[0046] Various aspects of the present invention may be implemented
as circuit-based solutions, including possible implementation on a
single integrated circuit. As would be apparent to one skilled in
the art, various functions of circuit elements may also be
implemented as processing operations in a software program. Such
software may be employed in, for example, a digital signal
processor, a microcontroller, a special-purpose computer, or a
general-purpose computer.
[0047] The present invention can be embodied in the form of
methods, and apparatus for practicing those methods. Various
aspects of the present invention can also be embodied in the form
of program code embodied in tangible media, such as punched cards,
magnetic tape, floppy disks, hard disk drives, CD-ROMs, flash
memory cards, or any other machine-readable storage medium,
wherein, when the program code is loaded into and executed by a
machine, such as a computer, the machine becomes an apparatus for
practicing the invention. The present invention can also be
embodied in the form of program code, for example, whether stored
in a storage medium, loaded into and/or executed by a machine, or
transmitted over some transmission medium or carrier, such as over
electrical wiring or cabling, through fiber optics, or via
electromagnetic radiation, wherein, when the program code is loaded
into and executed by a machine, such as a computer, the machine
becomes an apparatus for practicing the invention. When implemented
on a general-purpose processor, the program code segments combine
with the processor to provide a unique device that operates in a
manner analogous to hardwired logic circuits.
[0048] While the present invention has been described in terms of
the above-described embodiments, those skilled in the art will
recognize that the invention is not limited to the embodiments
described. The present invention can be practiced with modification
and alteration within the spirit and scope of the appended claims.
Thus, the description herein is to be regarded as illustrative
rather than restrictive with respect to the present invention.
* * * * *