Method and system for waveguide delay based equalization with current and optical summing in optical communication

• US 10,554,310 B2
• Filed: 03/15/2019
• Issued: 02/04/2020
• Est. Priority Date: 06/30/2016
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Luxtera Incorporated (Cisco Systems, Inc.)
• Inventors: Pang, Simon, Balardeta, Joseph
• Primary Examiner(s): Sandhu, Amritbir K
• Application Number:
  US16/355,357
• Publication Number:
  US 20190215078A1
• Time in Patent Office: 326 Days
• Field of Search: 398202-214
• CPC Class Codes: G02B 6/34 utilising prism or grating G02B6/293 takes precedence
• CPC Class Codes: G02B 6/4246 Bidirectionally operating package structures
• CPC Class Codes: G02B 6/4295 coupling with semiconductor devices activated by light through the light guide, e.g. thyristors, phototransistors
• CPC Class Codes: G02F 1/212 Mach-Zehnder type
• CPC Class Codes: G02F 1/225 in an optical waveguide structure
• CPC Class Codes: H04B 10/25891 Transmission components H04B10/40 takes precedence
• CPC Class Codes: H04B 10/66 Non-coherent receivers, e.g. using direct detection
• CPC Class Codes: H04B 10/67 Optical arrangements in the receiver
• CPC Class Codes: H04B 10/6971 using equalisation

Abstract

Methods and systems for waveguide delay based equalization with current and optical summing in optical communication are disclosed and may include an optoelectronic receiver including a directional coupler, two or more photodetectors, and one or more current mirrors. The optoelectronic receiver may be operable to: receive an input optical signal; split the input optical signal into first and second optical signals using the directional coupler; generate a first electrical from the first optical signal using a first photodetector; generate a second electrical signal from the second optical signal using a second photodetector; mirror the second electrical signal using the current mirror; and sum the first electrical signal with the amplified second electrical signal. The optoelectronic receiver may be operable to delay the first optical signal before generating the first electrical signal, using a waveguide delay.

Claims

1. A method for communication, the method comprising:

in an optoelectronic receiver comprising a directional coupler, two or more photodetectors, and one or more current mirrors;

receiving an input optical signal;

splitting the input optical signal into first and second optical signals using the directional coupler;

generating a first electrical signal from the first optical signal using a first photodetector;

generating a second electrical signal from the second optical signal using a second photodetector;

mirroring the second electrical signal using one of the one or more current mirrors; and

summing the first electrical signal with the mirrored second electrical signal.

2. The method according to claim 1, comprising delaying the first optical signal before generating the first electrical signal.

3. The method according to claim 2, comprising delaying the first optical signal using a waveguide delay.

4. The method according to claim 1, comprising generating an equalized output voltage by coupling the summed first electrical signal and mirrored second electrical signal utilizing a transimpedance amplifier.

5. The method according to claim 1, comprising splitting the second optical signal into third and fourth optical signals using a second directional coupler before generating the second electrical signal.

6. The method according to claim 5, wherein the second photodetector comprises two inputs for receiving optical signals.

7. The method according to claim 5, comprising delaying the fourth optical signal using a waveguide delay.

8. The method according to claim 7, comprising coupling the delayed fourth optical signal to a third photodetector and summing its output current with an output current from the second photodetector.

9. The method according to claim 1, comprising weighting the first and second optical signals by configuring a coupling coefficient of the directional coupler.

10. The method according to claim 1, wherein the optoelectronic transceiver is on a silicon complementary-metal oxide semiconductor (CMOS) photonics die.

11. A system for communication, the system comprising:

an optoelectronic receiver comprising a directional coupler, two or more photodetectors, and one or more current mirrors, the optoelectronic receiver being operable to;

receive an input optical signal;

split the input optical signal into first and second optical signals using the directional coupler;

generate a first electrical signal from the first optical signal using a first photodetector;

generate a second electrical signal from the second optical signal using a second photodetector;

mirror the second electrical signal using one of the one or more current mirrors; and

sum the first electrical signal with the mirrored second electrical signal.

12. The system according to claim 11, wherein the optoelectronic receiver is operable to delay the first optical signal before generating the first electrical signal.

13. The system according to claim 12, wherein the optoelectronic receiver is operable to delay the first optical signal using a waveguide delay.

14. The system according to claim 11, wherein the optoelectronic receiver is operable to generate an equalized output voltage by coupling the summed first electrical signal and mirrored second electrical signal utilizing a transimpedance amplifier.

15. The system according to claim 11, wherein the optoelectronic receiver is operable to split the second optical signal into third and fourth optical signals using a second directional coupler before generating the second electrical signal.

16. The system according to claim 15, wherein the second photodetector comprises two inputs for receiving optical signals.

17. The system according to claim 15, wherein the optoelectronic receiver is operable to delay the fourth optical signal using a waveguide delay.

18. The system according to claim 15, wherein the optoelectronic receiver is operable to couple the delayed fourth optical signal to a third photodetector and sum its output current with an output current from the second photodetector.

19. The system according to claim 11, wherein the optoelectronic receiver is operable to weight the first and second optical signals by configuring a coupling coefficient of the directional coupler.

20. A system for communication, the system comprising:

an optoelectronic receiver comprising first and second directional couplers, first and second photodetectors, first and second waveguide delays, and a current mirror, the optoelectronic receiver being operable to;

receive an input optical signal;

split the input optical signal into first and second optical signals using the first directional coupler;

delay the first optical signal utilizing the first delay waveguide;

generate a first electrical signal from the delayed first optical signal using a first photodetector;

split the second optical signal into third and fourth optical signals;

delay the fourth optical signal using the second delay waveguide;

generate a second electrical signal from the third optical signal and the delayed fourth optical signal using the second photodetector;

mirror the second electrical signal using the current mirror; and

sum the first electrical signal with the mirrored second electrical signal.