Granted Patent B2

US 9,270,078 · App. 14/601,107 · Granted Feb 23, 2016

Abstract

Claims (43)

1. A wavelength tunable silicon-on-insulator (SOI) laser comprising:

a laser cavity including:

a semiconductor gain medium having a front end and a back end; and

a phase-tunable waveguide platform coupled to the front end of the semiconductor gain medium, the phase-tunable waveguide platform comprising:

a first ring resonator having a first free spectral range (FSR);

a second ring resonator having a second FSR different to the first FSR, the second ring resonator being coupled to the first ring resonator;

wherein, at least one of the ring resonators is a phase-tunable ring resonator

wherein each of the first ring resonator and the second ring resonator comprises a first half-ring and a second half-ring, the first half-ring coupled to the second half-ring; and

wherein the laser cavity further comprises a multimode interference (MMI) coupler to couple light into the first ring resonator, the MMI also forms an optical couple between the first half-ring of the first ring resonator and the second half-ring of the first ring resonator.

2. The wavelength tunable laser of claim 1 , wherein a mirror of the laser cavity is located at the back end of the semiconductor gain medium.

3. The wavelength tunable laser of claim 1 , further comprising a second MMI coupler to couple light into the second ring resonator; wherein the second MMI also forms a further optical couple between the first half-ring of the first ring resonator and the second half-ring of the first ring resonator.

4. The wavelength tunable laser of claim 3 , further comprising a third MMI coupler to couple light out of the second ring resonator, wherein the third MMI coupler also forms a mirror of the laser cavity as well as an optical couple between the first half-ring of the second ring resonator and the second half-ring of the second ring resonator.

5. The wavelength tunable laser of claim 3 , wherein the second MMI coupler also forms an optical couple between the first half-ring of the second ring resonator and the second half-ring of the second ring resonator to directly couple the first ring resonator to the second ring resonator.

6. The wavelength tunable laser of claim 3 , wherein the phase-tunable waveguide platform further comprises an additional 1×2 MMI coupler to couple light out of the first ring resonator.

7. A wavelength tunable silicon-on-insulator (SOI) laser comprising:

a laser cavity including:

a semiconductor gain medium having a front end and a back end; and

a phase-tunable waveguide platform coupled to the semiconductor gain medium, the phase-tunable waveguide platform comprising:

a first ring resonator having a first free spectral range (FSR);

a second ring resonator having a second FSR different from the first FSR, the second ring resonator being coupled to the first ring resonator;

wherein, at least one of the ring resonators is a phase-tunable ring resonator;

wherein a mirror of the laser cavity is located at the back end of the semiconductor gain medium; and

wherein each of the first ring resonator and the second ring resonator comprises a first half-ring and a second half-ring, the first half-ring coupled to the second half-ring by multimode interference couplers.

8. The wavelength tunable laser of claim 1 , wherein each ring resonator comprises a first half-ring with a first radius of curvature coupled to a second half-ring with a second radius of curvature, the second radius of curvature being less than the first radius of curvature.

9. The wavelength tunable laser of claim 8 , wherein the first half-ring and second half-ring are coupled to one another via a multimode interference coupler.

10. The wavelength tunable laser of claim 1 , wherein the phase-tunable ring resonator includes a phase tuning region which comprises an electro-optical medium.

11. The wavelength tunable laser of claim 1 , wherein the phase-tunable ring resonator includes a phase tuning region which comprises a p-i-n junction region.

12. The wavelength tunable laser of claim 1 , wherein the phase-tunable ring resonator includes a phase tuning region which comprises a p-n junction region.

13. The wavelength tunable laser of claim 1 , wherein both the first ring resonator and the second ring resonator are tunable ring resonators.

14. The wavelength tunable laser of claim 13 ,

wherein the phase tuning region of the first ring resonator is any one of: a p-n junction; p-i-n junction or electro-optical medium; and

wherein the phase tuning region of the second ring resonator is any one of: a p-n junction, p-i-n junction or electro-optical medium.

15. The wavelength tunable laser of claim 1 , wherein the phase-tunable waveguide platform includes bifurcated waveguides, each arm of the bifurcated waveguides comprising one ring resonator.

16. The wavelength tunable laser of claim 15 , wherein a bifurcated waveguide of the bifurcated waveguides is a Y-branch waveguide.

17. The wavelength tunable laser of claim 1 , wherein the first ring resonator and second ring resonator are fabricated in a nested configuration.

18. The wavelength tunable laser of claim 1 ; further comprising a phase tuning region which is separate from the first and second ring resonators.

19. The wavelength tunable laser of claim 18 , wherein one or more of said phase tuning region(s) comprise(s) an electro-optical medium.

20. The wavelength tunable laser of claim 18 , wherein one or more of said phase tuning region(s) include(s): a p-n junction or a p-i-n junction.

21. The wavelength tunable laser of claim 1 , wherein the phase-tunable waveguide platform comprises at least one transition region at which a waveguide of a first height is coupled to a waveguide of a second height; the second height being less than the first height.

22. The wavelength tunable laser of claim 21 , wherein at least one of the first and second ring resonators is located in a waveguide of a second height.

23. The wavelength tunable laser of claim 1 , wherein the phase-tunable waveguide platform comprises a transition region at which a waveguide of a first width is coupled to a waveguide of a second width; the second width being less than the first width.

24. The wavelength tunable laser of claim 23 , wherein at least one of the first and second ring resonators is located in a waveguide of said second width.

25. The wavelength tunable laser of claim 21 , wherein the transition region includes a taper or a mode transformer.

Assignments (11)