U.S. patent number RE44,107 [Application Number 12/961,270] was granted by the patent office on 2013-03-26 for multi-data-rate optical transceiver.
This patent grant is currently assigned to Source Photonics, Inc.. The grantee listed for this patent is Mingshou He, Yuanjun Huang, Jiang Tian, Bin Wei, Rangchen Yu. Invention is credited to Mingshou He, Yuanjun Huang, Jiang Tian, Bin Wei, Rangchen Yu.
United States Patent |
RE44,107 |
Yu , et al. |
March 26, 2013 |
Multi-data-rate optical transceiver
Abstract
An optical transceiver module includes an optical-to-electrical
converter configured to convert a first optical signal to a first
electric signal, a first amplifier configured to amplify the first
electric signal, a bandwidth controller coupled to the first
amplifier, configured to control the frequency response
characteristics of the amplification of the first amplifier to
produce a first amplified electric signal, a driver circuit
configured to receive a second electric signal and to produce a
second amplified electric signal in response to the second electric
signal and an optical feedback signal, an electrical-to-optical
converter coupled to the micro-controller and configured to convert
the second amplified electrical signal to a second optical signal,
and a photo diode configured to detect the second optical signal
and to produce the optical feedback signal to be received by the
driver circuit.
Inventors: |
Yu; Rangchen (San Jose, CA),
Huang; Yuanjun (Chengdu, CN), He; Mingshou
(Chengdu, CN), Wei; Bin (Chengdu, CN),
Tian; Jiang (Chengdu, CN) |
Applicant: |
Name |
City |
State |
Country |
Type |
Yu; Rangchen
Huang; Yuanjun
He; Mingshou
Wei; Bin
Tian; Jiang |
San Jose
Chengdu
Chengdu
Chengdu
Chengdu |
CA
N/A
N/A
N/A
N/A |
US
CN
CN
CN
CN |
|
|
Assignee: |
Source Photonics, Inc.
(Chatsworth, CA)
|
Family
ID: |
34678276 |
Appl.
No.: |
12/961,270 |
Filed: |
December 6, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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11257627 |
Oct 25, 2005 |
7200336 |
|
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Reissue of: |
11696065 |
Apr 3, 2007 |
7650077 |
Jan 19, 2010 |
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Current U.S.
Class: |
398/137;
398/136 |
Current CPC
Class: |
G02B
6/4246 (20130101); G02B 6/4277 (20130101) |
Current International
Class: |
H04B
10/00 (20060101) |
Field of
Search: |
;398/135,138,139,130,128,136,137 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
Chao Zhang, Xuefei Zeng, Zhong Yang, Yuanjun Huang, Qing Huang,
Zhiyong Jiang and Jun Cao; "Avalanche Photodiode Temp Bias Voltage
Tester"; esp@cenet; Chinese Publication No. CN2781392 (Y);
Publication Date: May 17, 2006; esp@cenet Database--Worldwide.
cited by applicant.
|
Primary Examiner: Sedighian; M. R.
Attorney, Agent or Firm: The Law Offices of Andrew D.
Fortney Fortney; Andrew D.
Parent Case Text
CROSS-REFERENCES TO RELATED INVENTIONS
.Iadd.The present application is a continuation of U.S. patent
application Ser. No. 11/257,627, filed on Oct. 25, 2005, now U.S.
Pat. No. 7,200,336. .Iaddend.The present invention is related to
commonly assigned U.S. patent application Ser. No. 10/741,805,
filed on Dec. 19, 2003, titled "Bi-directional optical transceiver
module having automatic-restoring unlocking mechanism", commonly
assigned U.S. patent application Ser. No. 10/815,326, filed on Apr.
01, 2004, titled "Small form factor pluggable optical transceiver
module having automatic-restoring unlocking mechanism and mechanism
for locating optical transceiver components", commonly assigned
U.S. patent application Ser. No. 10/850,216, filed on May 20, 2004,
titled "Optical Transceiver module having improved printed circuit
board", commonly assigned U.S. patent application Ser. No.
10/893,803, filed on Jul. 19, 2004, titled "Single fiber optical
transceiver module", and commonly assigned Chinese Patent
Application No. 200420034040.X filed on Jun. 15, 2004, titled "An
APD Bias Voltage Test Equipment". The disclosures of these related
applications are incorporated herein by reference.
Claims
What is claimed is:
1. An optical transceiver that receives and transmits signals of
various data rates and power levels, comprising: an electrical
interface comprising an electrical input port that receives an
input electrical signal, a first user command input port that
receives a first user command signal, an electrical output port
that outputs an electrical output signal and a second user command
input port that receives a second user command signal; an optical
interface comprising an optical input port that receives an input
optical signal based on which the electrical output signal is
generated at the electrical interface, and an optical output port
that outputs an optical output signal based on the electrical input
signal received at the electrical interface; a driver circuit
coupled to the electrical input port to receive the electrical
input signal and responsive to a control of the first user command
signal in converting the electrical input signal into a driver
signal at a data rate that is based on and varies with the first
user command signal, the driver circuit coupled to receive a power
feedback control signal and controlling a power level of the driver
signal based on the received power feedback control signal; an
electrical to optical converter coupled to the driver circuit to
convert the driver signal into the optical output signal carrying
data of the driver signal at the data rate; a monitoring photo
diode that detects light of the optical output signal to generate
the power feedback control signal to the driver circuit; an optical
to electrical converter coupled to the optical input port and
converting the input optical signal into a first electrical signal;
an amplifier coupled to the optical to electrical converter to
receive and amplify the first electrical signal to generate the
output electrical signal, the amplifier receiving a bandwidth
control signal and adjusting a bandwidth of the amplifier in
generating the output electrical signal in response to the
bandwidth control signal; and a bandwidth controller coupled to
receive the second user command signal and producing the bandwidth
control signal based on the second user command signal.
2. The optical transceiver as in claim 1, wherein the electrical
interface comprises a Physical Media Attachment block (PMA) coupled
to the amplifier and the driver circuit, configured to receive the
output from the amplifier and to transmit the input electrical
signal to the driver circuit.
3. The optical transceiver as in claim 2, wherein the electrical
interface comprises a Physical Coding Sublayer block (PCS) coupled
to the Physical Media Attachment block (PMA), configured to receive
output from the Physical Media Attachment block and .Iadd.transmits
.Iaddend.the input electrical signal to the Physical Media
Attachment block.
4. An optical transceiver that receives and transmits signals of
various data rates and power levels, comprising: an electrical
interface comprising an electrical input port that receives an
input electrical signal, and an electrical output port that outputs
an electrical output signal; an optical interface comprising an
optical input port that receives an input optical signal based on
which the electrical output signal is generated at the electrical
interface, and an optical output port that outputs an optical
output signal based on the electrical input signal received at the
electrical interface; a driver circuit coupled to the electrical
input port to receive the electrical input signal and responsive to
a transmitter data control signal in converting the electrical
input signal into a driver signal at a data rate that is based on
and varies with the transmitter data control signal, the driver
circuit coupled to receive a power feedback control signal and
controlling a power level of the driver signal based on the
received power feedback control signal; a transmitter data rate
detector coupled to detect a data rate of the input electrical
signal and producing the transmitter data control signal; an
electrical to optical converter coupled to the driver circuit to
convert the driver signal into the optical output signal carrying
data of the driver signal at the data rate; a monitoring photo
diode that detects light of the optical output signal to generate
the power feedback control signal to the driver circuit; an optical
to electrical converter coupled to the optical input port and
converting the input optical signal into a first electrical signal;
an amplifier coupled to the optical to electrical converter to
receive and amplify the first electrical signal to generate the
output electrical signal, the amplifier receiving a bandwidth
control signal and adjusting a bandwidth of the amplifier in
generating the output electrical signal in response to the
bandwidth control signal; a receiver data rate detector coupled to
detect a data rate of the first electrical signal output by the
optical to electrical converter and producing the receiver data
control signal based on the detected data rate; and a bandwidth
controller coupled to receive the receiver data control signal and
producing the bandwidth control signal based on the receiver data
control signal.
5. The optical transceiver as in claim 4, wherein the electrical
interface comprises a Physical Media Attachment block (PMA) coupled
to the amplifier and the driver circuit, configured to receive the
output from the amplifier and to transmit the input electrical
signal to the driver circuit.
6. The optical transceiver as in claim 5, wherein the electrical
interface comprises a Physical Coding Sublayer block (PCS) coupled
to the Physical Media Attachment block (PMA), configured to receive
output from the Physical Media Attachment block and transmits the
input electrical signal to the Physical Media Attachment block.
.Iadd.7. An optical transceiver, comprising: an electrical
interface that receives an input electrical signal and that outputs
an electrical output signal; an optical interface that receives an
input optical signal on which the electrical output signal is based
and that outputs an optical output signal based on the electrical
input signal; a driver circuit that converts the electrical input
signal into a driver signal, the driver circuit generating the
driver signal at a power that is based on a feedback control
signal; an electrical to optical converter coupled to the driver
circuit to convert the driver signal into the optical output
signal, the optical output signal carrying data of the driver
signal at a first data rate, the electrical to optical converter
outputting the optical output signal at a variable output power
controlled by a receiver data control signal; a photo diode that
monitors the optical output signal and generates the feedback
control signal; an optical to electrical converter that converts
the input optical signal into a first electrical signal; an
amplifier coupled to the optical to electrical converter to amplify
the first electrical signal and generate the output electrical
signal, the amplifier having a modifiable bandwidth that is
controlled by the receiver data control signal..Iaddend.
.Iadd.8. The optical transceiver as in claim 7, further comprising
a receiver data rate detector coupled to detect a data rate of the
first electrical signal, the receiver data rate detector producing
the receiver data control signal based on the detected data rate of
the first electrical signal..Iaddend.
.Iadd.9. The optical transceiver as in claim 7, wherein the
receiver data control signal is controlled by
software..Iaddend.
.Iadd.10. The optical transceiver as in claim 7, wherein the
optical interface determines an operation mode for the optical
transceiver through hand-shaking..Iaddend.
.Iadd.11. The optical transceiver as in claim 10, wherein the
operation mode sets the first data rate and a data rate of the
input optical signal through remote provisioning by a link
party..Iaddend.
.Iadd.12. The optical transceiver as in claim 8, wherein the
amplifier comprises (i) a transimpedance amplifier receiving the
first electrical signal and providing an amplified electrical
signal, and (ii) a limiting amplifier receiving the amplified
electrical signal and providing the output electrical
signal..Iaddend.
.Iadd.13. The optical transceiver as in claim 12, wherein the
receiver data rate detector controls a bandwidth of the
transimpedance amplifier, a difference in the bandwidth of the
transimpedance amplifier results in a difference in sensitivity of
the input optical signal, and the sensitivity of the input optical
signal is modified to fit a data rate of the input optical
signal..Iaddend.
.Iadd.14. The optical transceiver as in claim 8, wherein the
receiver data rate detector is configured to control frequency
response characteristics of the amplifier..Iaddend.
.Iadd.15. An optical transceiver, comprising: an electrical
interface that receives an input electrical signal and that outputs
an electrical output signal; an optical interface that receives an
input optical signal on which the electrical output signal is based
and that outputs an optical output signal based on the electrical
input signal; a driver circuit receiving the electrical input
signal or a variation thereof, and producing a driver signal at a
data rate that is based on and that varies with a transmitter data
control signal, the driver circuit receiving a feedback control
signal controlling a power of the driver signal; an electrical to
optical converter coupled to the driver circuit to convert the
driver signal into the optical output signal, the electrical to
optical converter outputting the optical output signal at a
variable output power that is based on and that varies with the
transmitter data control signal; a photo diode that monitors the
optical output signal and generates the feedback control signal; an
optical to electrical converter that converts the input optical
signal into a first electrical signal; an amplifier coupled to the
optical to electrical converter, to receive and amplify the first
electrical signal and generate the output electrical signal, the
amplifier having a modifiable bandwidth that is controlled by a
bandwidth control signal; and a bandwidth controller coupled to
receive the transmitter data control signal, the bandwidth
controller producing the bandwidth control signal..Iaddend.
.Iadd.16. The optical transceiver as in claim 15, wherein the photo
diode (i) monitors an intensity, power or strength of a monitoring
optical signal from the electrical to optical converter and (ii)
produces the feedback control signal in accordance with or based on
the intensity or strength of the monitoring optical
signal..Iaddend.
.Iadd.17. The optical transceiver as in claim 15, wherein the
driver circuit produces a bias voltage and a driving current for
the electrical to optical converter, and the feedback control
signal is configured to modify or adjust the bias voltage and/or
the driving current of the driver circuit to control the output
power of the optical output signal..Iaddend.
.Iadd.18. The optical transceiver as in claim 17, wherein the
output power of the optical output signal is regulated by an EEPROM
having values set by the feedback control signal..Iaddend.
.Iadd.19. The optical transceiver as in claim 17, further
comprising a micro-controller that controls the bias voltage and
the driver current of the driver circuit..Iaddend.
.Iadd.20. The optical transceiver as in claim 19, wherein the
electrical interface further comprises a user command input that
receives a user command signal, and the micro-controller receives
the user command signal..Iaddend.
.Iadd.21. The optical transceiver as in claim 19, wherein the
micro-controller includes a memory to store software
instructions..Iaddend.
.Iadd.22. The optical transceiver as in claim 19, further
comprising a transmitter data rate detector coupled to detect a
data rate of the electrical input signal and producing the
transmitter data control signal based on the detected data rate of
the first electrical signal..Iaddend.
.Iadd.23. The optical transceiver as in claim 15, wherein the
transmitter data control signal is controlled by
software..Iaddend.
.Iadd.24. An optical transceiver, comprising: an electrical
interface that receives an input electrical signal and that outputs
an electrical output signal; an optical interface that receives an
input optical signal on which the electrical output signal is based
and that outputs an optical output signal based on the electrical
input signal; a driver circuit receiving the electrical input
signal or a variation thereof, and producing a driver signal at a
data rate that is based on and that varies with a transmitter data
control signal, the driver circuit receiving a feedback control
signal controlling a power of the driver signal; an electrical to
optical converter coupled to the driver circuit to convert the
driver signal into the optical output signal, the electrical to
optical converter outputting the optical output signal at a
variable output power that is based on and that varies with the
transmitter data control signal; a photo diode that monitors the
optical output signal and that generates the feedback control
signal; an optical to electrical converter that converts the input
optical signal into a first electrical signal; an amplifier coupled
to the optical to electrical converter to amplify the first
electrical signal and generate the output electrical signal, the
amplifier having a modifiable bandwidth that is controlled by a
bandwidth control signal; and a bandwidth controller coupled to
receive a receiver data control signal, the bandwidth controller
producing the bandwidth control signal..Iaddend.
.Iadd.25. The optical transceiver as in claim 24, wherein a change
in data rate of the input optical signal changes the bandwidth of
the amplifier, and a change in the transmitter data control signal
changes a data rate and power of the optical output
signal..Iaddend.
.Iadd.26. The optical transceiver as in claim 24, wherein the
electrical interface further comprises a user command input that
receives a user command signal..Iaddend.
.Iadd.27. The optical transceiver as in claim 26, wherein the user
command signal consists of a single control signal that sets data
transmission and data reception at a same rate..Iaddend.
.Iadd.28. The optical transceiver as in claim 26, wherein the user
command signal comprises first and second control lines that allow
different data rates for data transmission and data
reception..Iaddend.
.Iadd.29. The optical transceiver as in claim 28, further
comprising a micro-controller that receives the transmitter data
control signal on the first control line, wherein the bandwidth
controller receives a second user command signal on the second
control line, the bandwidth controller producing the bandwidth
control signal based on the second user command
signal..Iaddend.
.Iadd.30. The optical transceiver as in claim 24, further
comprising: a) a receiver data rate detector coupled to detect a
data rate of the first electrical signal, the receiver data rate
detector producing a receiver data control signal based on the
detected data rate of the first electrical signal, and the
bandwidth controller producing the bandwidth control signal based
on the receiver data control signal; b) a transmitter data rate
detector coupled to detect a data rate of the electrical input
signal and producing a data rate set up signal; and c) a
micro-controller that receives the data rate set up signal and
controls a bias voltage and a driving current of the driver
circuit..Iaddend.
.Iadd.31. The optical transceiver as in claim 24, wherein the
bandwidth control signal is controlled by software..Iaddend.
.Iadd.32. The optical transceiver as in claim 24, wherein the
optical interface determines an operation mode for the optical
transceiver through hand-shaking, and the operation mode sets the
first data rate and a data rate of the input optical signal through
remote provisioning by a link party..Iaddend.
.Iadd.33. The optical transceiver as in claim 24, wherein the
amplifier comprises: a) a transimpedance amplifier receiving the
first electrical signal and providing an amplified electrical
signal, wherein the bandwidth controller controls a bandwidth of
the transimpedance amplifier, and b) a limiting amplifier receiving
the amplified electrical signal and providing the output electrical
signal..Iaddend.
.Iadd.34. The optical transceiver as in claim 24, wherein the
bandwidth controller is configured to control frequency response
characteristics of the amplifier..Iaddend.
.Iadd.35. A method of receiving and transmitting optical signals,
comprising: converting an electrical input signal into a driver
signal at a data rate that is based on and that varies with a first
command signal; converting the driver signal into an optical output
signal and at a variable output power that is based on and that
varies with the first command signal, the optical output signal
carrying data of the driver signal; converting an input optical
signal into a first electrical signal; and amplifying the first
electrical signal to generate an output electrical signal, the
first electrical signal having a modifiable bandwidth that is
controlled by a second command signal..Iaddend.
.Iadd.36. The method as in claim 35, wherein a difference in the
modifiable bandwidth of the first electrical signal results in a
difference in sensitivity of the input optical signal, and the
sensitivity of the input optical signal is modified to fit a data
rate of the input optical signal..Iaddend.
.Iadd.37. The method as in claim 35, wherein the first command
signal and the second command signal are represented by one or more
mode signals that set desired data rates for data transmission and
data reception..Iaddend.
.Iadd.38. The method as in claim 35, wherein a change in the first
command signal changes a data rate of the optical output signal,
and a change in the second command signal changes a data rate of
the optical input signal..Iaddend.
.Iadd.39. The method as in claim 35, wherein the power of the
driver signal corresponds to a bias voltage and a driving current,
and the method further comprises controlling a power of the driver
signal based on a feedback control signal, the feedback control
signal adjusting the bias voltage and/or the driving current to
control an output power of the optical output signal..Iaddend.
.Iadd.40. The method as in claim 35, further comprising determining
an operation mode for the optical transceiver through
hand-shaking..Iaddend.
.Iadd.41. The method as in claim 40, wherein the operation mode
sets the data rates of the driver signal and the input optical
signal through remote provisioning by a link party..Iaddend.
Description
TECHNICAL FIELD
This disclosure relates to electro-optical devices, specifically,
an optical transceiver.
BACKGROUND
An optical transceiver is a device that can .[.covert.].
.Iadd.convert .Iaddend.optical signals into electrical signals and
convert electrical signals into optical signals. Various standards
in the telecommunication and data communication industries specify
the rates of data transmissions. For example, the original Ethernet
standard has a data rate of 10 Mega bit per second (Mbps). Fast
Ethernet's data rate is 100 Mbps, and Gigabit Ethernet transmits
and receives data at a rate of 1000 Mbps. Compliance with the
standards is important for .[.inter-operatability.].
.Iadd.interoperability .Iaddend.between different vendors for a
wide range of commercial applications. Different industry standards
such as the IEEE standard include requirements on the optical
interface of an optical transceiver. Particularly, the average
output power of an optical transceiver for the 100 Mbps Ethernet is
between -20 and -15 dBm, while that for the 1000 Mbps Ethernet is
between -10 and 4 dBm. Similarly, the required average input power
for 100 Mbps Ethernet is from -30 dBm to -15 dBm while that for
1000 Mbps Ethernet is from -17 dBm to -3 dBm. The currently
commercially available optical transceivers interface include only
fixed data rate under a fixed optical specification. There is
therefore a need for networks operating at different data rates to
properly communicate with each other. There is also a need for
networks to upgrade to higher data rates without excessive costs
and time.
SUMMARY
In one aspect, the present invention relates to an optical
transceiver module, comprising an optical-to-electrical converter
configured to convert a first optical signal to a first electric
signal; a first amplifier configured to amplify the first electric
signal; a bandwidth controller coupled to the first amplifier,
configured to control the frequency response characteristics of the
amplification of the first amplifier to produce a first amplified
electric signal; a driver circuit configured to receive a second
electric signal and to produce a second amplified electric signal
in response to the second electric signal and an optical feedback
signal; an electrical-to-optical converter coupled to the
micro-controller and configured to convert the second amplified
electrical signal to a second optical signal; and a photo diode
configured to detect the second optical signal and to produce the
optical feedback signal to be received by the driver circuit.
In another aspect, the present invention relates to an optical
transceiver module, comprising an optical-to-electrical converter
configured to convert a first optical signal to a first electric
signal; a first amplifier configured to amplify the first electric
signal; a bandwidth controller coupled to the first amplifier,
configured to control the frequency response characteristics of the
amplification of the first amplifier to produce an first amplified
electric signal; a driver circuit configured to receive a second
electric signal and to produce an amplified electric signal in
response to the second electric signal and a optical feedback
signal; an electrical-to-optical converter coupled to the
micro-controller and configured to convert the amplified electrical
signal to a second optical signal; an optical data-rate detector
configured to detect the second optical signal and to produce the
optical feedback signal to be received by the driver circuit; an
optical interface configured to receive the first optical signal
and output the second optical signal; and an electrical interface
configured to receive the second electrical signal and output the
first amplified electrical signal.
In yet another aspect, the present invention relates to an optical
transceiver module, comprising an optical-to-electrical converter
configured to convert a first optical signal to a first electric
signal; a first amplifier configured to amplify the first electric
signal; a bandwidth controller coupled to the first amplifier,
configured to control the frequency response characteristics of the
amplification of the first amplifier to produce .[.an.]. .Iadd.a
.Iaddend.first amplified electric signal; a driver circuit
configured to receive a second electric signal and to produce an
amplified electric signal in response to the second electric signal
and .[.a.]. .Iadd.an .Iaddend.optical feedback signal; an
electrical-to-optical converter coupled to the micro-controller and
configured to convert the amplified electrical signal to a second
optical signal; an optical data-rate detector configured to detect
the second optical signal and to produce the optical feedback
signal to be received by the driver circuit; an optical interface
configured to receive the first optical signal and output the
second optical signal; and an electrical interface configured to
receive the second electrical signal and output the first amplified
electrical signal.
Embodiments may include one or more of the following advantages.
The disclosed system provides a flexible multi-rate optical
transceiver that enables a computer network to operate at different
data rates.
Another advantage of the disclosed system that it allows networks
or computer devices operating at different data rates to
communicate with each other.
Yet another advantage of the disclosed system that it provides
convenient means for upgrading a network or computer system from
one data rate to a different data rate. The manual unplugging and
plugging of optical transceivers on a network are eliminated during
a data rate upgrade.
Still another advantage of the disclosed system that the multi-rate
optical transceiver is more cost efficient by providing the
capability of communicating at multiple data rates in one optical
transceiver.
Another advantage of the disclosed system that it provides software
control of an optical interface to allow data transmission at
different data rates .[.and.]..Iadd., .Iaddend.compatible with
communication standards at the different data rates.
DESCRIPTION OF DRAWINGS
FIG. 1 is a perspective view of an exemplified optical transceiver
module in compatible with the present invention.
FIG. 2 is a chart for average power input and output for 100 Mbps
and 1000 Mbps Ethernet in accordance with the present
invention.
FIG. 3 is a block diagram for a multi-rate optical transceiver in
accordance with an embodiment of the present invention.
FIG. 4 is a block diagram for a multi-rate optical transceiver with
an electrical Media Independent Interface in accordance with
another embodiment of the present invention.
FIG. 5 is a block diagram for a multi-rate optical transceiver with
automatic data rate detection in accordance with another embodiment
of the present invention.
DETAILED DESCRIPTION
Reference will now be made in detail to the preferred embodiments
of the invention, examples of which are illustrated in the
accompanying drawings. While the invention will be described in
conjunction with the preferred embodiments, it will be understood
that they are not intended to limit the invention to these
embodiments. On the contrary, the invention is intended to cover
alternatives, modifications and equivalents, which may be included
within the spirit and scope of the invention as defined by the
appended claims. Furthermore, in the following detailed description
of the present invention, numerous specific details are set forth
in order to provide a thorough understanding of the present
invention. However, it will be obvious to one of conventional skill
in the art that the present invention may be practiced without
these specific details. In other instances, well known methods,
procedures, components, and circuits have not been described in
detail as not to unnecessarily obscure aspects of the present
invention.
FIG. 1 shows an optical transceiver 100 that can receive optical
signals from an optical fiber and .[.coverts.]. .Iadd.convert
.Iaddend.the received optical signals into electrical signals. The
optical transceiver 100 can also convert electrical signals into
optical signals and .[.transmits.]. .Iadd.transmit .Iaddend.the
converted optical signals to an optical fiber. The optical
transceiver 100 .[.include.]. .Iadd.includes .Iaddend.an electrical
to optical converter (for transmit purposes), and an
optical-to-electrical converter (for receive purposes), a driver
providing proper bias voltage and modulation for transmission
.Iadd.of .Iaddend.the output optical signals, and a limiting
amplifier providing proper signal amplification for the
optical-to-electrical converter.
It is desirable for an optical transceiver to be in compliance with
industry standards. The different industry standards have
.[.define.]. .Iadd.defined .Iaddend.requirements on the optical
interface and the electric interface of an optical transceiver. In
particular, different industry standards require different input
and output powers to and from an optical transceiver. FIG. 2 shows
an example of the average input and output power requirements for
100 Mbps and 1000 Mbps Ethernets.
A conventional optical transceiver is built to transmit and receive
data at a fixed data rate. An optical transceiver for 100 Mbps
Ethernet cannot be used on a 1000 Mbps Ethernet network. However,
it is very common that a server and its clients work at different
data rates (a server working at 1000 Mbps and some of its clients
working at 100 Mbps while its other clients working at 1000 Mbps
for example). In this situation, the server needs to be connected
with a plurality of optical transceivers that each operates at a
different data rate. Furthermore, when a communication device needs
to be upgraded from one data rate (e.g. 100 Mbps) to another data
rate (e.g. 1000 Mbps), all the old optical transceivers have to be
replaced by new optical transceivers capable of transmitting data
at the new data rate. The upgrade can thus be costly and time
consuming.
For an optical transceiver to operate on multiple data rates, it is
desirable to be able to transmit and receive data at multiple data
rates at both its electrical interface and its optical interface.
The industry standard interfaces for the electrical interface side
include for example the Media Independent Interface (MII) and the
Gigabit Media Independent Interface (GMII).
On the optical interface side, there has not been a standard
solution. The fundamental requirement for a multi-rate optical
transceiver is to enable the transceiver to transmit and receive
optical signals using a variable input power and a variable output
power that satisfy the requirements from various industry
standards. In particular, the electrical-to-optical converter needs
to output optical signals at a variable output power. The
optical-to-electrical converter needs to operate at different
sensitivities, in .[.reflect.]. .Iadd.respect .Iaddend.of different
input powers for different data rates.
.[.Refer.]. .Iadd.Referring .Iaddend.to FIG. 3, a block diagram
illustrating the transmission and reception paths of an optical
transceiver .Iadd.300 is shown.Iaddend.. In the transmission path,
the optical transceiver 300 receives a second electrical signal 330
(also referred to as an electrical transmission signal). The
electrical transmission signal 330 goes through block 312, which
generates a driver current for electrical to optical converter 311.
Block 312 also generates a bias voltage for the electrical to
optical converter 311. The driver current and the bias voltage are
controlled by .Iadd.a .Iaddend.micro-controller 313. The electrical
to optical converter 311 generates a second optical signal 360
(also referred to as an optical transmission signal). The optical
transmission signal 360 is monitored by monitoring photo-diode 317,
which sends a feedback signal through feedback control line 319 to
driver 312, so that the bias voltage and driving current can be
modified. When there is a change in data rate at the electrical
transmission signal 330, the data rate of the optical transmission
output signal 360 can be changed by a user command line 340.
Through the user command line 340, a control signal is sent to
micro-controller 313. The micro-controller 313 controls the driver
312 that produces .Iadd.the .Iaddend.bias voltage and driving
current for electrical to optical converter 311. Different bias
voltages and driving currents can cause the electrical to optical
converter 311 to produce different output .[.power.]. .Iadd.powers
.Iaddend.for the optical transmission signal 360.
The output power of the optical output signal 360 can be further
controlled by .[.a.]. .Iadd.an .Iaddend.optical feedback signal
through the feedback control line 319. A monitoring photo diode 317
receives and monitors the intensity of the monitoring optical
signal 321 from the electrical to optical converter 311 and
produces the feedback control signal in accordance with the
intensity of the monitoring optical signal 321. The feedback signal
can adjust the bias voltage or driving current of block 312 to
control the output power of the optical transmission signal
360.
In the reception path, the optical transceiver 300 takes a first
optical signal (i.e. the optical reception signal) 350, and the
optical reception signal 350 is converted to a first electrical
signal (i.e. the reception electrical signal) at
optical-to-electrical converter 314. The converted electrical
signal is amplified by Trans-Impedance Amplifier (TIA) 315,
followed by a limiting amplifier 316. The amplification can be
modified by TIA bandwidth controller 318.
When there is a change in the data rate in the optical reception
signal 350, the sensitivity for the optical reception signal 350
needs to be modified to fit the reception data rate. This is done
by the bandwidth controller user command input 370. This control
signal is received by bandwidth controller 318, which controls the
bandwidth of the Trans-Impedance Amplifier 315. Different bandwidth
at the TIA 315 makes the sensitivity of the electrical signal from
the optical-to-electrical converter 314 different. Thus the optical
transceiver 300 can be adjusted to receive data at different data
rates.
A variety of implementations exist for the control lines 340 and
370. Control lines 340 and 370 can be a single control that can set
data transmission and reception at the same data rate.
Alternatively, the control lines 340 and 370 can be implemented by
two separate control lines, allowing different data rates for data
transmission and reception. In one implementation of the control
lines 340 and 370, the control lines simply send a "mode" signal,
informing the optical transceiver the desired data rate to be set.
Once the mode signal is received, the optical transceiver is
programmed to automatically set the operation parameters to a set
of pre-determined values such that the proper data rate can be
achieved. The "mode" signals can be prepared and stored in one of
the following forms:
1. a programmable logic such as CPLD or FPGA
2. a memory device, such as EEPROM
3. a micro-controller (with .[.build.]. .Iadd.built .Iaddend.in
memory to store software instruction)
In another implementation of the control lines 340 and 370, the
controls are achieved through an "in-band" hand-shaking from the
optical interface. The operation mode of the optical transceiver is
determined through this hand shake optical interface, by an
intelligent data processing unit so that the optical transceiver
can be set at the proper data rate through the "remote"
provisioning by the link party at the far side.
FIG. 4 illustrates another optical transceiver 400. In the
transmission path, the optical transceiver 400 receives an
electrical transmission signal at a Physical Coding Sublayer (PCS)
block 420 which in turn transmits the electrical transmission
signal to a Physical Media Attachment (PMA) block 419. The
electrical transmission signal from the PMA block 419 goes through
block 412, which generates a driver current for electrical to
optical converter 411. Block 412 also generates a bias voltage for
the electrical to optical converter 411. The driver current and the
bias voltage are controlled by micro-controller 413. The electrical
to optical converter 411 generates an optical transmission signal
470. The optical transmission signal 470 is monitored by monitoring
photo-diode 417, which sends a feedback signal through feedback
control line 490 to driver 412, so that the bias voltage and
driving current can be modified.
When there is a change in data rate at the electrical transmission
signal .[.430.]. .Iadd.440.Iaddend., the data rate of the optical
transmission output signal 470 can be changed by a user command
line 450. Through the user command line 450, a control signal is
sent to micro-controller 413, which controls the driver 412 which
in turn produces the bias voltage and driving current for
electrical to optical converter 411. Different bias voltages and
driving currents cause the electrical to optical converter 411 to
produce different output power for the optical transmission signal
470.
The output power of the optical output signal 470 can be further
regulated by setting different values to an EEPROM POT in the
control feedback loop .[.. . ..]. by the optical feedback signal
through the feedback control line 490, which is generated by
monitoring photo diode 417. The monitoring photo diode 417 receives
and monitors the strength of a monitoring optical signal 421 from
the electrical to optical converter 411. Based on the strength of
the monitoring optical signal 421, the monitoring photo-diode 417
produces the feedback control signal on the feedback control line
490. The feedback signal reduces or increases the bias voltage or
driving current of block 412, which results in a reduction or
increase in the output power of the optical transmission signal
470.
In the reception path, the optical transceiver 400 receives an
optical reception signal 460, and the optical reception signal 460
is converted to a reception electrical signal at
optical-to-electrical converter 414. The converted electrical
reception signal is amplified by Trans-Impedance Amplifier (TIA)
415, followed by a limiting amplifier 416. The amplification can be
modified by TIA bandwidth controller 418.
When there is a change in the data rate in the optical reception
signal 460, the optical reception signal 460 is modified to fit the
reception data rate by adjusting controller user command input 480
to the bandwidth controller. Based on the user command input 480,
the bandwidth of Trans-Impedance amplifier 415 can be modified.
Different bandwidths at the TIA 415 can result in different
sensitivities to the electrical signal in the optical-to-electrical
converter 414. Thus the optical transceiver 400 can be adjusted to
receive data at different data rates.
The PMA 419 and PCS 420 are electric circuits that enable in the
compatibility with the Ethernet standards such as the Media
Independent Interface (MII) standard or the Gigabit Media
Independent Interface (GMII). With the configuration in FIG. 4, the
interface of signals 430 and 440 become "universal" with any GMII
(Gigabit Media Independent Interface) type of interfaces. With a
GMII interface, data can be transmitted at different data rate such
as 100 Mbps or Gigabit Ethernet through the same interface without
any need for changing the physical optical interface device. This
is achieved by integrating the intelligence of switching the
operation mode of PHY also inside the transceiver. Data Encoding
and Decoding can be conducted without any physical change. For
example 100 M Ethernet requires 4B/5B CODEC while Gigabit Ethernet
requires 8B/10B CODEC. With this "switchable" function integrated
into the optical transceiver, it becomes a "universal device" for
running both Fast Ethernet and Gigabit Ethernet. A user can attach
this device to their MII or GMII based MAC interface and set data
rate by software commands without changing the physical
configuration of the device.
In another embodiment, the optical transceiver's transmission and
reception data rates can be detected and the optical transceiver's
operation mode can be set automatically based on the detected
transmit and reception data rates. FIG. 5 shows the block diagram
for an optical transceiver 500. As .Iadd.for .Iaddend.optical
transceiver 400, optical transceiver 500 has a Physical Coding
Sublayer (PCS) block 520 at its electrical interface. At this
interface, electrical transmission signal 540 enters the PCS 520
and electrical reception signal 530 is sent out by the PCS 520. The
PCS 520 is coupled with a Physical Media Attachment (PMA) block
519. The combination of the PCS 520 and the PMA 519 makes the
electrical interface a standard Ethernet interface making it
possible for the optical transceiver to be connected directly to an
Ethernet Media Access Controller (MAC) block.
On the optical interface, the optical transmission signal 570 is
the output from the electrical-to-optical converter 511. The
optical reception signal 560 enters the optical-to-electrical
converter 514. The major control of the output power of optical
transmission signal 570 is from control input 550, and a fine tune
control signal 590 comes from monitoring photo-diode 517. The
control of the input sensitivity of optical reception signal 560 is
through bandwidth controller 518, which is controlled by control
signal 581. Unlike .[.ptical.]. .Iadd.optical .Iaddend.transceiver
400, whose data rate is entirely controlled by user command lines,
optical transceiver 500 can detect the data rates at the electrical
transmission signal 540 and the reception optical signal 560.
In the transmission direction, the transmission data rate detector
521 detects the electrical transmission signal 540 and measures the
transmission signal data rate. One possible implementation of the
data rate detector 521 can comprise a clock recovery circuit and a
counter. The counter of clock cycles is an indication of the data
rate. Based on the measured transmission signal data rate, the
transmission data rate detector 521 generates a Micro-controller
data rate set up input signal 550 and sends this control signal to
micro-controller 513.
In the data-reception path, the reception data rate detector 580
receives the electrical reception signal from output of the
optical-to-electrical converter 514 and measures the data rate of
this signal. Based on the measured data rate of the input optical
data, the reception data rate detector 580 generates a bandwidth
controller set up input 581, and sends this control signal to
bandwidth controller 518. With the detection of the transmission
and reception data rates, the data rates of the optical transceiver
500 can be automatically set by the data rate detectors 521 and
580, thus the user command lines can be eliminated.
The disclosed system includes the following advantages over the
conventional single-data-rate optical transceiver: (1) A multi-rate
optical transceiver makes it possible to a network to operate at
different data rates or for networks or computer devices operating
at different data rates to communicate with each other. (2) A
multi-rate optical transceiver makes it more convenient to upgrade
a network from one data rate to a higher data rate. No unplugging
and plugging of optical transceivers on a network is needed during
a data rate upgrade. (3) A multi-rate optical transceiver is more
cost efficient. The multi-rate optical transceiver can operate on
multiple data rates, while several conventional single-data-rate
optical transceivers are required to operate at different data
rates.
PART NUMBERS
100 optical transceiver module 110 module housing 120 shielding
metal cover 130 electrical interface 140 optical interface 200 a
chart for average input and output powers of 100 Mbps and 1000 Mbps
Ethernet 311 Electrical to optical converter device 312 driver
circuits 313 micro-controller/EEPOT 314 optical-to-electrical
converter 315 trans-impedance amplifier 316 limiting amplifier 317
monitoring photo-diode 318 trans-impedance amplifier bandwidth
control 319 feedback control line 320 electrical signal output 321
monitoring optical signal 330 electrical signal input 340
micro-controller user command input 350 optical signal input 360
optical signal output 370 bandwidth controller user command input
411 electrical to optical converter device 412 driver circuits 413
micro-controller/EEPOT 414 optical-to-electrical converter 415
trans-impedance amplifier 416 limiting amplifier 417 Monitoring
photo-diode 418 Trans-impedance amplifier bandwidth control 419
Physical Media Attachment (PMA) 420 Physical Coding Sublayer (PCS)
430 Media Independent Interface (MII) electrical signal output 440
Media Independent Interface (MII) electrical signal input 450
Micro-controller user command input line 460 Optical signal input
470 optical signal output 480 bandwidth controller user command
input .Iadd.490 feedback control line.Iaddend. 511 electrical to
optical converter device 512 driver circuits 513
micro-controller/EEPOT 514 optical-to-electrical converter 515
trans-impedance amplifier 516 limiting amplifier 517 monitoring
photo-diode 518 trans-impedance amplifier bandwidth control 519
Physical Media Attachment (PMA) 520 Physical Coding Sublayer (PCS)
521 .[.Rx.]. .Iadd.Tx .Iaddend.data rate detector 530 Media
Dependent Interface electrical signal output 540 Media Dependent
Interface electrical signal input 550 Micro-controller data rate
set up input 560 optical signal input 570 optical signal output 580
.[.Tx.]. .Iadd.Rx .Iaddend.data rate detector 581 Bandwidth
controller set up input .Iadd.590 fine tune control
signal.Iaddend.
* * * * *