Tunable laser with directional coupler

Patent metadata

Field	Value
Publication number	US-10862270-B2
Application number	US-201916374293-A
Country	US
Kind code	B2
Filing date	Apr 3, 2019
Priority date	Mar 7, 2014
Publication date	Dec 8, 2020
Grant date	Dec 8, 2020

Abstract

A tunable laser has a first mirror, a second mirror, a gain medium, and a directional coupler. The first mirror and the second mirror form an optical resonator. The gain medium and the directional coupler are, at least partially, in an optical path of the optical resonator. The first mirror and the second mirror comprise binary super gratings. Both the first mirror and the second mirror have high reflectivity. The directional coupler provides an output coupler for the tunable laser.

First claim

What is claimed is:

1. A device for a laser comprising:
a first mirror having a first plurality of reflectance peaks;
a second mirror having a second plurality of reflectance peaks, wherein the first mirror and the second mirror are configured to form a resonator;
a gain medium within the resonator; and
a coupler between the first mirror and the second mirror, the coupler configured to guide a selected percentage of light directly, not evanescently, out of the resonator through a port of the coupler, such that the selected percentage of light coupled out of the resonator is independent of spectral properties of the first mirror and the second mirror, and wherein the coupler is a waveguide coupler.

2. The device of claim 1 , wherein:
wherein a maximum reflectance of the first plurality of reflectance peaks is greater than 90%; and
wherein a maximum reflectance of the second plurality of reflectance peaks is greater than 90%.

3. The device of claim 1 , wherein:
the coupler comprises a ridge portion having a width at a waist of the coupler, wherein the waist is at a center of the coupler; and
the selected percentage of light guided out of the resonator through the port of the coupler is based on the width of the ridge portion at the waist of the coupler.

4. The device of claim 1 , wherein:
the coupler comprises a first ridge and a second ridge;
a gap separates the first ridge from the second ridge; and
the gap is equal to or greater than 0.75 microns.

5. The device of claim 1 , wherein the first mirror, the second mirror, the gain medium, and the coupler are integrated on a substrate.

6. The device of claim 1 , wherein the coupler is a directional coupler having four ports.

7. The device of claim 1 , wherein there is not more than a 10% difference in a maximum reflectance of the first plurality of reflectance peaks and a maximum reflectance of the second plurality of reflectance peaks.

8. The device of claim 1 , wherein the first mirror comprises a binary super grating (BSG) having a first number of super periods;
the second mirror comprises a BSG having a second number of super periods; and
the first number of super periods equals the second number of super periods.

9. The device of claim 1 , wherein the port is coupled with a crystalline silicon waveguide.

10. The device of claim 1 , wherein a length of the coupler is less than 120 microns.

11. A method comprising:
amplifying light in a resonator using a gain medium, wherein the resonator is formed by a first mirror and a second mirror; and
coupling light out of the resonator, using a waveguide coupler, wherein the waveguide coupler is configured to guide a selected percentage of light directly, not evanescently, out of the resonator through a port of the waveguide coupler, such that the selected percentage of light coupled out of the resonator is independent of spectral properties of the first mirror and the second mirror.

12. The method of claim 11 , further comprising aligning a reflectance peak of the first mirror with a reflectance peak of the second mirror by heating the first mirror and/or the second mirror.

13. The method of claim 11 , further comprising coupling light into the port using a ridge taper.

14. The method of claim 11 , wherein the waveguide coupler comprises a ridge portion, and the method further comprises designing a width of the ridge portion for a given coupling efficiency of the waveguide coupler.

15. The method of claim 11 , wherein:
a maximum reflectance of the first mirror is equal to or greater than 80% and less than 100%; and
a maximum reflectance of the second mirror is equal to or greater than 80% and less than 100%.

16. A device comprising:
a first mirror;
a second mirror, wherein the first mirror and the second mirror are configured to form a resonator; and
a waveguide coupler configured to guide a selected percentage of light directly, not evanescently, out of the resonator through a port of the waveguide coupler.

17. The device of claim 16 , wherein:
the first mirror has a first plurality of reflectance peaks;
the second mirror has a second plurality of reflectance peaks;
the device comprise a gain medium within the resonator;
the waveguide coupler is between the first mirror and the second mirror; and
the waveguide coupler couples light out of the resonator independent of spectral properties of the first mirror and the second mirror.

18. The device of claim 16 , wherein:
the port is a first port; and
the device further comprises a diode coupled with a second port of the waveguide coupler.

19. The device of claim 16 , wherein:
the waveguide coupler comprises a ridge portion having a width at a waist of the waveguide coupler, wherein the waist is at a center of the waveguide coupler; and
the selected percentage of light guided out of the resonator through the port of the waveguide coupler is based on the width of the ridge portion at the waist of the waveguide coupler.

20. The device of claim 16 , wherein:
a maximum reflectance of the first mirror is equal to or greater than 80% and less than 100%; and
a maximum reflectance of the second mirror is equal to or greater than 80% and less than 100%.

Assignees

• Skorpios Tech Inc

Inventors

• Chaouch Hacene
• Li Guoliang

Classifications

• G02B6/125 Primary

  Bends, branchings or intersections · CPC title

• H01S5/12 Primary

  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) · CPC title

• H01S3/1055

  one of the reflectors being constituted by a diffraction grating · CPC title

• H01S5/1218

  in superstructured configuration, e.g. more than one period in an alternate sequence · CPC title

• H01S5/0612

  controlled by temperature · CPC title