Tunable laser using microring resonator

• US 20030219045A1
• Filed: 05/14/2002
• Published: 11/27/2003
• Est. Priority Date: 05/14/2002
• Status: Active Grant

• Current Assignee: Lambda Crossing Ltd.
• Original Assignee: Lambda Crossing Ltd.
• Inventors: Margalit, Moti, Orenstein, Meir
• Granted Patent: US 6,940,878 B2
• Time in Patent Office: Days
• US Class Current: 372/20
• CPC Class Codes: H01S 5/06255 Controlling the frequency of the radiation
• CPC Class Codes: H01S 5/1032 Coupling to elements comprising an optical axis that is not aligned with the optical axis of the active region
• CPC Class Codes: H01S 5/1071 Ring-lasers
• CPC Class Codes: H01S 5/12 the resonator having a periodic structure, e.g. in distributed feedback [DFB] lasers comprising a photonic bandgap structure H01S5/11; surface-emitting lasers H01S5/18

Abstract

A tunable semiconductor laser device is presented. The device comprises a laser structure formed by at least two waveguides and an active region located within at least a segment of one of the waveguides; and comprises a tunable spectral filter optically coupled to the laser structure. The tunable spectral filter includes at least two filtering elements, at least one of them being a microring cavity.

Claims

1. A tunable semiconductor laser device comprising a laser structure formed by at least two waveguides and an active region located within at least a segment of one of the waveguides;

and a tunable spectral filter optically coupled to the laser structure, said tunable spectral filter including a least two filtering elements, at least one of the filtering elements being microring cavity.

2. The device according to claim 1, wherein the microring cavity filter element filters a frequency comb, and the other bandpass filtering element selects a specific frequency from the filtered frequency comb.

3. The device according to claim 2, wherein dimensions of said microring cavity provide for generating the frequency comb with a required spacing between output frequency components.

4. The device according to claim 3, wherein said bandpass filtering element is tunable.

5. The device according to claim 4, wherein said bandpass filtering element is an additional microring cavity.

6. The device according to claim 5, wherein said additional microring cavity has smaller dimensions than said microring cavity.

7. The device according to claim 5, wherein the two microring cavities are horizontally coupled to the active region waveguide, and the other waveguide is coupled to the microrings.

9. The device according to claim 5, wherein the microrings are directly vertically coupled to the active region waveguide.

10. The device according to claim 5, wherein the microrings are vertically coupled to the waveguide containing the active region through segments of said waveguide outside said active region.

11. The device according to claim 5, wherein the microrings are coupled to the waveguide segments outside the active region, and said segments are vertically coupled to the active region waveguide.

12. The device according to claim 5, wherein the microrings are coupled to the waveguide segments outside the active region, and said segments are vertically coupled to the waveguide containing said active region through segments of said waveguide outside the active region.

13. The device according to claim 11, comprising an additional coupler element for coupling the microrings to the waveguide containing said active region.

14. The device according to claim 13, wherein said additional coupler element has a bandpass filtering function.

15. The device according to claim 12, comprising an additional coupler element for coupling the microrings to the waveguide containing said active region.

16. The device according to claim 15, wherein said additional coupler element has a bandpass filtering function.

17. The device according to claim 4, wherein said bandpass filtering element is a grating assisted coupler.

18. The device according to claim 1, wherein the microring cavity filtering element filters a first frequency comb, and the other filtering element filters a second frequency comb with a spectral spacing different from that of the first frequency comb.

19. The device according to claim 18, operable to perform frequency tuning using the Vernier effect.

20. The device according to claim 18, wherein the other filtering element is an additional microring cavity structure.

21. The device according to claim 18, wherein he other filtering element is a Fabry Perot microcavity.

22. The device according to claim 18, wherein the other filtering element includes sampled grating or superstructure gratings.

23. The device according to claim 1, wherein said two waveguides are coupled to each other by an arc segment to return filtered light back to the active region.

8. The device according to FIG. 5, wherein the microrings are horizontally coupled to the waveguide containing said active region through segments of said waveguide outside the active region.

24. A method of tuning a semiconductor laser device, which comprises a laser structure formed by two waveguides and an active region located within at least a segment of one of the waveguides, and comprises a tunable spectral filter including at least two microcavity rings optically coupled to the laser structure, and coupled to each other, the method comprising applying a field to tune the microrings relatively to each other to apply a Vernier effect.