Method and System For An Optoelectronic Built-In Self-Test System For Silicon Photonics Optical Transceivers

• US 20190327036A1
• Filed: 07/03/2019
• Published: 10/24/2019
• Est. Priority Date: 06/26/2014
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Luxtera Incorporated (Cisco Systems, Inc.)
• Inventors: Gloeckner, Steffen, Sahni, Subal, Balardeta, Joseph, Pang, Simon, Barabas, Stefan, Denton, Scott
• Granted Patent: US 10,721,035 B2
• Time in Patent Office: Days
• CPC Class Codes: H04B 10/0779 Monitoring line transmitter or line receiver equipment
• CPC Class Codes: H04B 10/40 Transceivers
• CPC Class Codes: H04B 10/801 using optical interconnects, e.g. light coupled isolators, circuit board interconnections
• CPC Class Codes: H04L 1/243 at the transmitter, using a loop-back
• CPC Class Codes: H04L 1/244 test sequence generators

Abstract

Methods and systems for an optoelectronic built-in self-test (BIST) system for silicon photonics optical transceivers may include an optoelectronic transceiver having a transmit (Tx) path and a receive (Rx) path, where the Rx path includes a main Rx path and a BIST loopback path. The system may generate a pseudo-random bit sequence (PRBS) signal, generate an optical signal in the Tx path by applying the PRBS signal to a modulator, communicate the optical signal to the BIST loopback path and convert the optical signal to an electrical signal utilizing a photodetector, where the photodetector is a replica of a photodetector in the main Rx path, and assess the performance of the Tx and Rx paths by extracting a PRBS signal from the electrical signal. The transceiver may be on a single complementary-metal oxide semiconductor (CMOS) die, or on two CMOS die where a first comprises electronic devices and a second comprises optical devices.

Claims

1. A method for optical communication, the method comprising:

in an optoelectronic transceiver having a transmit (Tx) path and a receive (Rx) path, the Rx path comprising a main Rx path and a built-in self-test loopback path;

multiplexing a pseudo-random bit sequence (PRBS) signal with an input electrical signal;

generating an optical signal in the Tx path by applying the multiplexed input electrical signal and PRBS signal to an optical modulator;

communicating the optical signal to a portion of the built-in self-test loopback path;

converting the optical signal to an electrical signal in the Rx path utilizing a loopback photodetector in the built-in self-test loopback path, the loopback photodetector being a replica of a photodetector in the main Rx path;

multiplexing the electrical signal in the Rx path with another electrical signal from the main Rx path; and

assessing performance of the Tx and Rx paths by reducing an input power of the optical signal in the Tx path while monitoring a bit error rate.

2. The method according to claim 1, wherein the transceiver is, at least in part, on an optoelectronics die that comprises a silicon photonic interposer.

3. The method according to claim 1, wherein the transceiver is, at least in part, on one or more electronics die that comprises one or more complementary-metal oxide semiconductor (CMOS) die.

4. The method according to claim 1, wherein the transceiver is on an optoelectronics die and one or more electronics die, and wherein the one or more electronics die is bonded directly to the optoelectronics die.

5. The method according to claim 4, wherein the one or more electronics die is coupled to the optoelectronics die using copper pillars.

6. The method according to claim 1, wherein the optical modulator comprises a Mach-Zehnder Interferometer.

7. The method according to claim 1, wherein a transimpedance amplifier coupled to an output of the loopback photodetector in the self-test loopback path is a replica of a transimpedance amplifier coupled to an output of a photodetector in the main Rx path.

8. The method according to claim 1, comprising extracting the PRBS signal and the input electrical signal from the electrical signal utilizing a demultiplexer in the Rx path.

9. The method according to claim 1, comprising receiving a second optical signal in the main Rx path.

10. The method according to claim 9, comprising generating a second electrical signal from the received second optical signal utilizing the photodetector in the main Rx path.

11. The method according to claim 10, comprising multiplexing the electrical signal in the Rx path with the second electrical signal.

12. A system for communication, the system comprising:

an optoelectronic transceiver having a transmit (Tx) path and a receive (Rx) path, the Rx path comprising a main Rx path and a built-in self-test loopback path, the optoelectronic transceiver being operable to;

multiplex a pseudo-random bit sequence (PRBS) signal with an input electrical signal;

generate an optical signal in the Tx path by applying the multiplexed PRBS signal and input electrical signal to an optical modulator;

communicate the optical signal to the built-in self-test loopback path;

convert the optical signal to an electrical signal in the Rx path utilizing a loopback photodetector in the built-in self-test loopback path, the loopback photodetector being a replica of a photodetector in the main Rx path; and

multiplex the electrical signal in the Rx path with an electrical signal from the photodetector in the main Rx path.

13. The system according to claim 12, wherein the optoelectronic transceiver is in a silicon photonically-enabled integrated circuit.

14. The system according to claim 13, wherein the silicon photonically-enabled integrated circuit is in a single complementary-metal oxide semiconductor (CMOS) die.

15. The system according to claim 13, wherein the silicon photonically-enabled integrated circuit is in two die, a first die comprising electronic devices and a second die comprising optical devices.

16. The system according to claim 15, wherein the two die comprise CMOS die.

17. The system according to claim 12, wherein the optical modulator comprises a Mach-Zehnder Interferometer.

18. The system according to claim 12, wherein a transimpedance amplifier coupled to an output of the loopback photodetector in the self-test loopback path is a replica of a transimpedance amplifier coupled to an output of a photodetector in the main Rx path.

19. The system according to claim 12, wherein the optoelectronic transceiver is operable to extract the PRBS signal and the input electrical signal from the electrical signal utilizing a demultiplexer in the Rx path.

20. The system according to claim 12, wherein the optoelectronic transceiver is operable to receive a second optical signal in the main Rx path.

21. The system according to claim 20, wherein the optoelectronic transceiver is operable to generate a second electrical signal from the received second optical signal utilizing the photodetector in the main Rx path and multiplex the electrical with the second electrical signal.

22. A method for communication, the method comprising:

in an optoelectronic transceiver on an optoelectronics die and one or more electronics die, the transceiver having a transmit (Tx) path and a receive (Rx) path, the Rx path comprising a main Rx path and a built-in self-test loopback path;

multiplexing a first electrical signal in the Tx path with a pseudo-random bit sequence (PRBS) signal in the at least one of the one or more electronics die;

generating a first optical signal in the Tx path by applying the multiplexed electrical and PRBS signals to an optical modulator in the optoelectronics die;

receiving a second optical signal in the Rx path and converting to a second electrical signal utilizing a photodetector in the main Rx path;

communicating the first optical signal to a portion of the built-in self-test loopback path in the optoelectronics die;

converting the first optical signal to a third electrical signal in the Rx path utilizing a loopback photodetector in the built-in self-test loopback path, the loopback photodetector being a replica of a photodetector in the main Rx path;

multiplexing the second and third electrical signals in the Rx path in the at least one of the one or more electronics die; and

assessing performance of the Tx and Rx paths by reducing an input power of the optical signal in the Tx path while monitoring a bit error rate.

23. A method for communication, the method comprising:

in an optoelectronic transceiver on an optoelectronics die and one or more electronics die, the transceiver having a transmit (Tx) path and a receive (Rx) path;

multiplexing a pseudo-random bit sequence (PRBS) signal with an input electrical signal;

generating an optical signal in the Tx path by applying the multiplexed PRBS signal and input electrical signal to an optical modulator in the optoelectronics die;

communicating the optical signal to a portion of the Rx path in the optoelectronics die;

converting the optical signal to an electrical signal in the Rx path utilizing a photodetector in the optoelectronics die and assessing performance of the Tx and Rx paths by reducing an input power of the optical signal in the Tx path while monitoring a bit error rate.