Method and system for waveguide delay based equalization with summing at single-ended to differential converters in optical communication
Methods and systems for waveguide delay based equalization summing at single-ended to differential converters in optical communication are disclosed and may include: in an optoelectronic receiver including a directional coupler, photodetectors, transimpedance amplifiers (TIAs), and a gain stage, receiving an input optical signal; splitting the input optical signal into first and second optical signals using the directional coupler; generating a first current from the first optical signal using a first photodetector; generating a first voltage from the first current using a first TIA; communicating the first voltage to a first input of the gain stage; generating a second current from the second optical signal using a second photodetector; generating a second voltage from the first signal using a second TIA; communicating the second voltage to a second input of the gain stage; and generating a differential output voltage from the first and second voltages using the gain stage.
1. A method for communication, the method comprising:
in an optoelectronic receiver comprising a directional coupler, first and second photodetectors, first and second transimpedance amplifiers (TIAs), and a gain stage:
receiving an input optical signal;
splitting the input optical signal into first and second optical signals using the directional coupler;
delaying the first optical signal received from the directional coupler using an optical delay at an output of the directional coupler;
generating a first electrical current from the first optical signal using the first photodetector;
generating a first voltage from the first electrical current using the first TIA;
communicating the first voltage to a first input of the gain stage;
generating a second electrical current from the second optical signal using the second photodetector;
generating a second voltage from the first electrical signal using the second TIA;
communicating the second voltage to a second input of the gain stage; and
generating a differential output voltage from the first and second voltages using the gain stage.
2. The method according to claim 1 , comprising delaying the first optical signal using a waveguide delay.
3. The method according to claim 2 , wherein the waveguide delay is coupled to an output of the directional coupler.
4. The method according to claim 1 , wherein the first and second photodetectors comprise photodiodes.
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 , comprising coupling the delayed fourth optical signal to a third photodetector and summing its output current with an output current from the second photodetector.
7. The method according to claim 1 , comprising weighting the second optical signal by configuring a gain of the second TIA.
8. The method according to claim 1 , comprising weighting the second optical signal by configuring a gain of the second TIA.
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 receiver 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, first and second photodetectors, first and second transimpedance amplifiers (TIAs), and a gain stage, 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;
delay the first optical signal received from the directional coupler using an optical delay at an output of the directional coupler;
generate a first electrical current from the first optical signal using the first photodetector;
generate a first voltage from the first electrical current using the first TIA;
communicate the first voltage to a first input of the gain stage;
generate a second electrical current from the second optical signal using the second photodetector;
generate a second voltage from the first electrical signal using the second TIA;
communicate the second voltage to a second input of the gain stage; and
generate a differential output voltage from the first and second voltages using the gain stage.
12. The system according to claim 11 , wherein the optoelectronic receiver is operable to delay the first optical signal using a waveguide delay.
13. The system according to claim 12 , wherein the waveguide delay is coupled to an output of the directional coupler.
14. The system according to claim 11 , wherein the first and second photodetectors comprise photodiodes.
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 optoelectronic receiver is operable to couple the delayed fourth optical signal to a third photodetector and summing its output current with an output current from the second photodetector.
17. The system according to claim 11 , wherein the optoelectronic receiver is operable to weight the first optical signal by configuring a gain of the first TIA.
18. The system according to claim 11 , wherein the optoelectronic receiver is operable to weight the second optical signal by configuring a gain of the second TIA.
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 in a complementary metal-oxide semiconductor (CMOS) die, said optoelectronic receiver comprising a directional coupler, first and second photodetectors, first and second transimpedance amplifiers (TIAs), and a gain stage, 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;
delay the first optical signal using an optical delay at an output of the directional coupler;
generate a first electrical current from the delayed first optical signal using the first photodetector;
generate a first voltage from the first electrical current using the first TIA;
communicate the first voltage to a first input of the gain stage;
generate a second electrical current from the second optical signal using the second photodetector;
generate a second voltage from the first electrical signal using the second TIA;
communicate the second voltage to a second input of the gain stage; and
generate a differential output voltage from the first and second voltages using the gain stage.