Method and system for integrated power combiners

1. A system comprising:

a combiner operable to:

generate a first optical signal and a second optical signal from a grating coupler that receives two or more optical signals of arbitrary polarization;

phase modulate one or both of the first optical signal and the second optical signal to configure a first phase offset between the first optical signal and the second optical signal;

communicate the first optical signal and the second optical signal with the first phase offset to a first optical coupler;

phase modulate one or both of a third optical signal and a fourth optical signal output from the first optical coupler to configure a second phase offset between the third optical signal and the fourth optical signal; and

after phase modulation of one or both the third optical signal and the fourth optical signal, combine the third optical signal and the fourth optical signal using a second optical coupler to launch a first output signal, having an optical power of essentially zero, into a first output waveguide of the second optical coupler and to launch a second output signal, having a maximized optical power, into a second output waveguide of the second optical coupler.

2. The system according to claim 1 , wherein one or both of the first optical coupler and the second optical coupler comprise a directional coupler.

3. The system according to claim 1 , wherein one or both of the first optical coupler and the second optical coupler comprise a multi-mode interference coupler.

4. The system according to claim 1 , wherein one or both of the first optical coupler and the second optical coupler comprise a multi-stage cascaded directional coupler.

5. The system according to claim 1 , wherein the combiner is integrated on a CMOS chip.

6. The system according to claim 1 , wherein optical detectors are operable to monitor optical power in waveguides coupling the first optical coupler and the second optical coupler, wherein monitoring of optical power is used to determine a desired phase offset between signals received at one or both of the first optical coupler and the second optical coupler.

7. The system according to claim 6 , wherein optical taps in the waveguides communicate optical signals to the optical detectors.

8. The system according to claim 1 , wherein the combiner comprises a plurality of stages.

9. A method comprising:

outputting from a grating coupler that receives an input signal comprising two or more optical signals of arbitrary polarization, a first optical signal and a second optical signal;

phase modulating one or both of the first and second optical signals to configure a first phase offset between the first and second output signals;

communicating the first and second optical signals with the first phase offset to a first optical coupler;

phase modulating one or both of a third optical signal and a fourth optical signal output from the first optical coupler to configure a second phase offset between the third and fourth optical signals;

launching a first output signal, having an optical power of essentially zero, into a first output waveguide of a second optical coupler; and

launching a second output signal, having a maximized optical power, into a second output waveguide of the second optical coupler.

10. The method according to claim 9 , wherein one or both of the first optical coupler and the second optical coupler comprise a directional coupler.

11. The method according to claim 9 , wherein one or both of the first optical coupler and the second optical coupler comprise a multi-mode interference coupler.

12. The method according to claim 9 , wherein one or both of the first optical coupler and the second optical coupler comprise a multi-stage cascaded directional coupler.

13. The method according to claim 9 , wherein the method is performed in a combiner integrated on a CMOS chip.

14. The method according to claim 13 , wherein the combiner comprises a plurality of stages.

15. The method according to claim 13 , wherein the combiner comprises a single stage.

16. The method according to claim 9 , comprising monitoring optical power in waveguides coupling the first optical coupler and the second optical coupler using optical detectors, wherein monitoring of optical power is used to determine a desired phase offset between signals received at one or both of the first optical coupler and the second optical coupler.

17. A combiner operable to:

receive, in a first optical coupler, a first optical signal and a second optical signal having arbitrary polarization;

generate a first phase offset between the first and second optical signals to output a third optical signal and a fourth optical signal;

generate a second phase offset between the third and fourth optical signals to output a fifth optical signal and a sixth optical signal;

combine, in a second optical coupler, the fifth optical signal and the sixth optical signal to produce a combined optical signal, having essentially all optical power from the fifth optical signal and the sixth optical signal, and a cancelled optical signal,

monitor, via optical detectors, optical power in waveguides coupling the first optical coupler and the second optical coupler to determine a desired phase offset between two optical signals received at one or both of the first optical coupler and the second optical coupler; and

output the combined output signal having a combined optical power of the fifth and sixth optical signals.

18. The combiner of claim 17 , wherein the second optical coupler includes a first output waveguide on which the combined optical signal is carried and a second output waveguide on which the cancelled optical signal is carried.