Ring-resonator-based laser with multiple wavelengths

Patent metadata

Field	Value
Publication number	US-2018159293-A1
Application number	US-201615047090-A
Country	US
Kind code	A1
Filing date	Feb 18, 2016
Priority date	Feb 18, 2016
Publication date	Jun 7, 2018
Grant date	—

Abstract

An optical source includes semiconductor optical amplifiers, with a semiconductor other than silicon, which provide an optical gain medium. Moreover, a photonic chip in the optical source, which is optically coupled to the semiconductor optical amplifiers, includes ring resonators that selectively pass corresponding optical signals having carrier wavelengths provided by the semiconductor optical amplifiers, where a given ring resonator and a reflector on one of the semiconductor optical amplifier defines an optical cavity, and the ring resonators have different radii with associated resonance wavelengths corresponding to the carrier wavelengths. Furthermore, the photonic chip includes a shared ring resonator, optically coupled to the ring resonators, that selectively filters the optical signals, where the shared ring resonator has a different radius than the radii of the ring resonators with an associated resonance wavelength, and a free-spectral range of the shared ring resonator defines a spacing between the carrier wavelengths in the optical signal.

First claim

What is claimed is:

1 . An optical source, comprising:
semiconductor optical amplifiers defined in a semiconductor other than silicon and having first edges and second edges, wherein the first edges are optically coupled to reflective elements, and wherein, during operation, the semiconductor optical amplifiers provide optical signals having different carrier wavelengths at the second edges; and a photonic chip optically coupled to the semiconductor optical amplifiers, wherein the photonic chip includes:
first optical waveguides having third edges and fourth edges, wherein the third edges are optically coupled to corresponding second edges of the semiconductor optical amplifiers and, during operation, the first optical waveguides convey the optical signals;
ring resonators, optically coupled to the first optical waveguides between the third edges and the fourth edges, that, during operation, selectively pass corresponding optical signals having the carrier wavelengths, wherein the ring resonators and the reflective elements define optical cavities, and wherein the ring resonators have different radii with associated resonance wavelengths corresponding to the carrier wavelengths;
a shared optical waveguide having a fifth edge and a sixth edge, wherein the shared optical waveguide is optically coupled to the ring resonators between the fifth edge and the sixth edge and, during operation, the shared optical waveguide conveys an optical signal having the carrier wavelengths; and
a shared ring resonator, optically coupled to the shared optical waveguide, that, during operation, selectively passes the optical signal, wherein the shared ring resonator has a different radius than the radii of the ring resonators with an associated resonance wavelength, and
wherein one of a free-spectral range of the shared ring resonator and a multiple of the free-spectral range defines a spacing between the carrier wavelengths in the optical signal;

2 . The optical source of claim 1 , wherein the optical source further comprises a second optical waveguide having a seventh edge, optically coupled to the shared ring resonator, that, during operation, conveys the optical signal.

3 . The optical source of claim 2 , wherein the optical source further comprises first photodetectors, optically coupled to the fourth edges, that, during operation, monitor the carrier wavelengths in the optical signals.

4 . The optical source of claim 3 , further comprising:
a thermal-tuning mechanism thermally coupled to the ring resonators; and control logic, electrically coupled to the thermal-tuning mechanism and the first photodetectors, that, during operation, tunes the resonance wavelengths of the ring resonators based on the carrier wavelengths monitored by the first photodetectors.

5 . The optical source of claim 4 , wherein the optical source further comprises:
a second photodetector, optically coupled to the sixth edge, that, during operation, monitors the carrier wavelengths in the optical signal; a third photodetector, optically coupled to the seventh edge, that, during operation, monitors the carrier wavelengths in the optical signal.

6 . The optical source of claim 5 , wherein the thermal-tuning mechanism is thermally coupled to the shared ring resonator and the control logic is electrically coupled to the second photodetector and the third photodetector; and
wherein, during operation, the control logic tunes the resonance wavelength of the shared ring resonator based on the carrier wavelengths monitored by at least one of the second photodetector and the third photodetector.

7 . The optical source of claim 4 , wherein the thermal-tuning mechanism includes one of: a doped semiconductor heater; and a metal heater.

8 . The optical source of claim 2 , wherein the optical source further comprises third optical waveguides that are optically coupled to the first optical waveguides and that, during operation, output the optical signals on edges of the third optical waveguides.

9 . The optical source of claim 1 , wherein the second optical waveguide has an eighth edge that is optically coupled to the shared optical waveguide; and
wherein the optical signal is output from the optical source at the fifth edge of the shared optical waveguide.

10 . The optical source of claim 9 , wherein the optical coupling between the first optical waveguides and the ring resonators is critically coupled, and the optical coupling between the ring resonators and the shared optical waveguide is under coupled.

11 . The optical source of claim 1 , wherein the second optical waveguide has an eighth edge and the second optical waveguide is optically coupled to the shared optical waveguide; and
wherein the optical signal is output from the optical source at the eighth edge of the second optical waveguide.

12 . The optical source of claim 11 , wherein the optical coupling between the first optical waveguides and the ring resonators is near critically coupled, and the optical coupling between the ring resonators and the shared optical waveguide is near critically coupled.

13 . The optical source of claim 1 , wherein the fourth edges of the first optical waveguides output the optical signals.

14 . The optical source of claim 13 , wherein the optical coupling between the first optical waveguides and the ring resonators is under coupled, and the optical coupling between the ring resonators and the shared optical waveguide is critically coupled.

15 . The optical source of claim 1 , wherein the optical coupling between the shared optical waveguide and the shared ring resonator and the optical coupling between the shared ring resonator and the second optical waveguide are symmetric.

16 . The optical source of claim 1 , wherein a given ring resonator and the shared ring resonator are a Vernier ring pair in which a combined free-spectral range of the optical source is a least common multiple of a free-spectral range of the given ring resonator and the free-spectral range of the shared ring resonator.

17 . The optical source of claim 1 , wherein the photonic chip includes:
a substrate; a buried-oxide layer disposed on the substrate; and a semiconductor layer that is one of disposed on the buried-oxide layer and bonded to the buried-oxide layer, wherein optical components are defined in the semiconductor layer.

18 . The optical source of claim 1 , wherein a combined free-spectral range of a given ring resonator and the shared ring resonator is greater than a gain bandwidth of a given semiconductor optical amplifier that corresponds to the given ring resonator.

19 . A system, comprising:
a processor; a memory coupled to the processor; and an optical source, wherein the optical source includes:
semiconductor optical amplifiers defined in a semiconductor other than silicon and having first edges and second edges, wherein the first edges are optically coupled to reflective elements, and wherein, during operation, the semiconductor optical amplifiers provide optical signals having different carrier wavelengths at the second edges; and
a photonic chip optically coupled to the semiconductor optical amplifiers, wherein the photonic chip includes:
first optical waveguides having third edges and fourth edges, wherein the third edges are optically coupled to corresponding second edges of the semiconductor optical amplifiers and, during operation, the first optical waveguides convey the optical signals;
ring resonators, optically coupled to the first optical waveguide

Assignees

• Oracle Int Corp

Inventors

• Bovington Jock T
• Zheng Xuezhe

Classifications

• H01S5/142

  which comprises an additional resonator · CPC title

• G02F2203/58

  Multi-wavelength, e.g. operation of the device at a plurality of wavelengths · CPC title

• H01S5/1071

  Ring-lasers · CPC title

• H01S5/4068

  with lateral coupling by axially offset or by merging waveguides, e.g. Y-couplers · CPC title

• H01S3/06791

  Fibre ring lasers (fibre laser gyrometers G01C19/72) · CPC title