Method and system for a free space CWDM MUX/DEMUX for integration with a grating coupler based silicon photonics platform

1. A method for communication, the method comprising:

in an optical assembly coupled to a top surface of a photonic chip, the optical assembly comprising a lens array on the top surface of the photonic chip, an angled mirror, a plurality of transparent spacers, and a plurality of thin film filters:

receiving an input optical signal comprising a plurality of optical signals at different wavelengths via an optical fiber coupled to the optical assembly;

communicating the plurality of optical signals through a first of the plurality of transparent spacers;

focusing the optical signal received from the optical fiber onto a first of the plurality of thin film filters using a silicon lens;

passing a first of the plurality of optical signals through the first of the plurality of thin film filters while reflecting others of the plurality of optical signals back into the first of the plurality of transparent spacers;

reflecting the others of the plurality of signals towards a second of the plurality of thin film filters via a reflective surface of the first of the plurality of transparent spacers;

passing one of the others of the plurality of optical signals through the second of the plurality of thin film filters; and

reflecting the passed optical signals into the photonic chip using the angled mirror.

2. The method according to claim 1 , wherein each of the thin film filters is configured for one of the different wavelengths of the plurality of optical signals.

3. The method according to claim 1 , wherein the input optical signal is a coarse wavelength division multiplexed (CWDM) signal.

4. The method according to claim 1 , wherein the optical assembly comprises a second lens array on the top surface of the photonic chip, a second angled mirror, a second plurality of transparent spacers, and a second plurality of thin film filters.

5. The method according to claim 4 , comprising receiving a second input optical signal comprising a second plurality of optical signals at different wavelengths via a second optical fiber coupled to the optical assembly and a first of the second plurality of transparent spacers.

6. A system for communication, the system comprising:

an optical assembly coupled to a top surface of a photonic chip, the optical assembly comprising a lens array on the top surface of the photonic chip, an angled mirror, a plurality of transparent spacers, and a plurality of thin film filters, the optical assembly being operable to:

receive an input optical signal comprising a plurality of optical signals at different wavelengths via an optical fiber coupled to the optical assembly;

communicating the plurality of optical signals through a first of the plurality of transparent spacers;

focus the optical signal received from the optical fiber onto a first of the plurality of thin film filters using a silicon lens;

pass a first of the plurality of optical signals through the first of the plurality of thin film filters while reflecting others of the plurality of optical signals back into the first of the plurality of transparent spacers;

reflect the others of the plurality of signals towards a second of the plurality of thin film filters via a reflective surface of the first of the plurality of transparent spacers;

pass one of the others of the plurality of optical signals through the second of the plurality of thin film filters; and

reflect the passed optical signals into the photonic chip using the angled mirror.

7. The system according to claim 6 , wherein each of the thin film filters is configured for one of the different wavelengths of the plurality of optical signals.

8. The system according to claim 6 , wherein the input optical signal is a coarse wavelength division multiplexed (CWDM) signal.

9. The system according to claim 6 , wherein the optical assembly comprises a second lens array on the top surface of the photonic chip, a second angled mirror, a second plurality of transparent spacers, and a second plurality of thin film filters.

10. The system according to claim 9 , wherein the optical assembly is operable to receive a second input optical signal comprising a second plurality of optical signals at different wavelengths via a second optical fiber coupled to the optical assembly and a first of the second plurality of transparent spacers.

11. A method for communication, the method comprising:

in an optical assembly coupled to a top surface of a photonic chip, the optical assembly comprising a lens array on the top surface of the photonic chip, an angled mirror, a plurality of transparent spacers, and a plurality of thin film filters:

receiving a plurality of optical signals at different wavelengths in the optical assembly from the photonic chip via the lens array;

reflecting the plurality of optical signals into a first of the transparent spacers using the angled mirror;

passing at least a first and a second of the plurality of optical signals through a corresponding first and second thin film filter into a second of the transparent spacers;

passing a third of the plurality of optical signals through the first of the transparent spacers into the second of the transparent spacers without passing through a thin film filter;

reflecting the second of the plurality of signals onto the first thin film filter via a reflective surface of the first of the plurality of transparent spacers;

successively reflecting the third of the plurality of optical signal between the reflective surface and the thin film filters until it reflects off of the first thin film filter; and

coupling the plurality of optical signals into an optical fiber coupled to the optical assembly.

12. The method according to claim 11 , comprising focusing the optical signals into the optical fiber using a silicon lens.

13. The method according to claim 11 , wherein each of the thin film filters is configured for one of the different wavelengths of the plurality of optical signals.

14. The method according to claim 11 , wherein the coupling of the plurality of optical signals into the optical fiber generates a coarse wavelength division multiplexed (CWDM) signal.

15. The method according to claim 11 , wherein the optical assembly comprises a second lens array on the top surface of the photonic chip, a second angled mirror, a second plurality of transparent spacers, and a second plurality of thin film filters.

16. The method according to claim 15 , comprising receiving a second plurality of optical signals at different wavelengths via the second lens array and reflecting them using the second angled mirror to the second plurality of thin film filters via the second plurality of transparent spacers.

17. A system for communication, the system comprising:

an optical assembly coupled to a top surface of a photonic chip, the optical assembly comprising a lens array on the top surface of the photonic chip, an angled mirror, a plurality of transparent spacers, and a plurality of thin film filters, the optical assembly being operable to:

receive a plurality of optical signals at different wavelengths in the optical assembly from the photonic chip via the lens array;

reflect the plurality of optical signals into a first of the transparent spacers using the angled mirror;

pass at least a first and a second of the plurality of optical signals through a corresponding first and second thin film filter into a second of the transparent spacers;

pass a third of the plurality of optical signals through the first of the transparent spacers into the second of the transparent spacers without passing through a thin film filter;

reflect the second of the plurality of signals onto the first thin film filter via a reflective surface of the first of the plurality of transparent spacers;

successively reflect the third of the plurality of optical signal between the reflective surface and the thin film filters until it reflects off of the first thin film filter; and

couple the plurality of optical signals into an optical fiber coupled to the optical assembly.

18. The system according to claim 17 , wherein the optical assembly is operable to focus the optical signals into the optical fiber using a silicon lens.

19. The system according to claim 17 , wherein each of the thin film filters is configured for one of the different wavelengths of the plurality of optical signals.

20. The system according to claim 17 , wherein the coupling of the plurality of optical signals into the optical fiber generates a coarse wavelength division multiplexed (CWDM) signal.

21. The system according to claim 17 , wherein the optical assembly comprises a second lens array on the top surface of the photonic chip, a second angled mirror, a second plurality of transparent spacers, and a second plurality of thin film filters.

22. The system according to claim 21 , wherein the optical assembly is operable to receive a second plurality of optical signals at different wavelengths via the second lens array and reflect them using the second angled mirror to the second plurality of thin film filters via the second plurality of transparent spacers.

23. A method for communication, the method comprising:

in an optical assembly coupled to a top surface of a photonic chip, the optical assembly comprising a lens array on the top surface of the photonic chip, an angled mirror, a plurality of transparent spacers, a plurality of thin film filters, a second lens array on the top surface of the photonic chip, a second angled mirror, a second plurality of transparent spacers, and a second plurality of thin film filters:

receiving an input optical signal comprising a plurality of optical signals at different wavelengths via an optical fiber coupled to the optical assembly;

communicating the plurality of optical signals through a first of the plurality of transparent spacers;

passing a first of the plurality of optical signals through a corresponding one of the plurality of thin film filters while reflecting others of the plurality of optical signals back into the first of the plurality of transparent spacers;

reflecting the others of the plurality of signals towards a second of the plurality of thin film filters via a reflective surface of the first of the plurality of transparent spacers;

passing one of the others of the plurality of optical signals through the second of the plurality of thin film filters; and

reflecting the passed optical signals into the photonic chip using the angled mirror.

24. The method according to claim 23 , wherein each of the thin film filters is configured for one of the different wavelengths of the plurality of optical signals.

25. The method according to claim 23 , wherein the input optical signal is a coarse wavelength division multiplexed (CWDM) signal.

26. The method according to claim 23 , comprising receiving a second input optical signal comprising a second plurality of optical signals at different wavelengths via a second optical fiber coupled to the optical assembly and a first of the second plurality of transparent spacers.

27. A system for communication, the system comprising:

an optical assembly coupled to a top surface of a photonic chip, the optical assembly comprising a lens array on the top surface of the photonic chip, an angled mirror, a plurality of transparent spacers, a plurality of thin film filters, a second lens array on the top surface of the photonic chip, a second angled mirror, a second plurality of transparent spacers, and a second plurality of thin film filters, the optical assembly being operable to:

receive an input optical signal comprising a plurality of optical signals at different wavelengths via an optical fiber coupled to the optical assembly;

communicating the plurality of optical signals through a first of the plurality of transparent spacers;

pass a first of the plurality of optical signals through a corresponding one of the plurality of thin film filters while reflecting others of the plurality of optical signals back into the first of the plurality of transparent spacers;

reflect the others of the plurality of signals towards a second of the plurality of thin film filters via a reflective surface of the first of the plurality of transparent spacers;

pass one of the others of the plurality of optical signals through the second of the plurality of thin film filters; and

reflect the passed optical signals into the photonic chip using the angled mirror.

28. The system according to claim 27 , wherein each of the thin film filters is configured for one of the different wavelengths of the plurality of optical signals.

29. The system according to claim 27 , wherein the input optical signal is a coarse wavelength division multiplexed (CWDM) signal.

30. The system according to claim 27 , wherein the optical assembly is operable to receive a second input optical signal comprising a second plurality of optical signals at different wavelengths via a second optical fiber coupled to the optical assembly and a first of the second plurality of transparent spacers.