Integrated laser with back-reflection isolator

Patent metadata

Field	Value
Publication number	US-2016294155-A1
Application number	US-201514821453-A
Country	US
Kind code	A1
Filing date	Aug 7, 2015
Priority date	Apr 1, 2015
Publication date	Oct 6, 2016
Grant date	—

Abstract

An integrated circuit includes an optical source (such as a laser) with a lens, which is disposed on an isolator. This isolator is disposed on a semiconductor layer in a silicon-on-insulator (SOI) platform that includes an optical coupler and an optical waveguide. During operation, the optical source generates an optical signal that propagates toward the isolator so that the lens focuses the optical signal. Furthermore, the isolator reduces or eliminates back reflection of the optical signal toward the optical source, and the optical coupler couples the optical signal into the optical waveguide.

First claim

What is claimed is:

1 . An integrated circuit, comprising:
a substrate; a buried-oxide (BOX) layer disposed on the substrate; a semiconductor layer disposed on the BOX layer, wherein the semiconductor layer includes an optical coupler and an optical waveguide, and wherein, during operation, the optical coupler couples an optical signal into the optical waveguide; an isolator disposed on the semiconductor layer; and an optical source, disposed on the isolator, which includes a lens, wherein, during operation, the optical source generates the optical signal that propagates toward the isolator, and the lens focuses the optical signal; and wherein, during operation, the isolator reduces back reflection of the optical signal toward the optical source.

2 . The integrated circuit of claim 1 , wherein the optical coupler includes a grating coupler.

3 . The integrated circuit of claim 1 , wherein the isolator includes:
a half-wave plate that, during operation, produces a π phase shift between polarization components along an ordinary axis and extraordinary axis in the optical signal and that rotates a polarization plane of the optical signal by twice an angle between an optical axis of the half-wave plate and an input polarization of the optical signal; a Faraday rotator; and a polarizer.

4 . The integrated circuit of claim 3 , wherein the polarizer is aligned with the optical source so that a polarization of the optical signal propagating from the optical source toward the optical coupler passes through the polarizer.

5 . The integrated circuit of claim 3 , wherein the polarizer is aligned with the half-wave plate.

6 . The integrated circuit of claim 3 , wherein the Faraday rotator produces a 45° phase shift between the horizontal and the vertical polarization components in the optical signal.

7 . The integrated circuit of claim 3 , wherein the Faraday rotator is disposed on the polarizer, and the half-wave plate is disposed on the Faraday rotator.

8 . The integrated circuit of claim 1 , wherein the optical source generates the optical signal in a plane and a mirror in the optical source reflects the optical signal at an angle relative to the plane; and
wherein the angle is other than 90°.

9 . The integrated circuit of claim 1 , wherein the lens is offset in a horizontal direction from a location of the optical coupler so that, during operation, the optical signal propagates through the isolator to the optical coupler.

10 . The integrated circuit of claim 1 , wherein the optical source includes a laser.

11 . A system, comprising:
a processor; a memory, coupled to the processor, that stores a program module, which, during operation, is executed by the processor; and an integrated circuit, wherein the integrated circuit includes:
a substrate;
a buried-oxide (BOX) layer disposed on the substrate;
a semiconductor layer disposed on the BOX layer, wherein the semiconductor layer includes an optical coupler and an optical waveguide, and wherein, during operation, the optical coupler couples an optical signal into the optical waveguide;
an isolator disposed on the semiconductor layer; and
an optical source, disposed on the isolator, which includes a lens, wherein, during operation, the optical source generates the optical that propagates toward the isolator, and the lens focuses the optical signal; and
wherein, during operation, the isolator reduces back reflection of the optical signal toward the optical source.

12 . The system of claim 11 , wherein the optical coupler includes a grating coupler.

13 . The system of claim 11 , wherein the isolator includes:
a half-wave plate that, during operation, produces a π phase shift between polarization components along an ordinary axis and extraordinary axis in the optical signal and that rotates a polarization plane of the optical signal by twice an angle between an optical axis of the half-wave plate and an input polarization of the optical signal; a Faraday rotator; and a polarizer.

14 . The system of claim 13 , wherein the polarizer is aligned with the optical source so that a polarization of the optical signal propagating from the optical source toward the optical coupler passes through the polarizer.

15 . The system of claim 13 , wherein the polarizer is aligned with the half-wave plate.

16 . The system of claim 13 , wherein the Faraday rotator produces a 45° phase shift between the horizontal and the vertical polarization components in the optical signal.

17 . The system of claim 13 , wherein the Faraday rotator is disposed on the polarizer, and the half-wave plate is disposed on the Faraday rotator.

18 . The system of claim 11 , wherein the optical source generates the optical signal in a plane and a mirror in the optical source reflects the optical signal at an angle relative to the plane; and
wherein the angle is other than 90°.

19 . The system of claim 11 , wherein the lens is offset in a horizontal direction from a location of the optical coupler so that, during operation, the optical signal propagates through the isolator to the optical coupler.

20 . A method for optically coupling an optical signal into an optical waveguide, comprising:
generating the optical signal in a plane of an optical source; reflecting the optical signal at an angle relative to the plane using a minor; focusing the optical signal; propagating the optical signal through an isolator that reduces back reflection of the optical signal toward the optical source, wherein the optical source is disposed on the isolator; and optically coupling the optical signal into the optical waveguide using an optical coupler, wherein the isolator is disposed on a semiconductor layer that includes the optical coupler and the optical waveguide; wherein the semiconductor layer is disposed on a buried-oxide (BOX) layer; and wherein the BOX layer is disposed on a substrate.

Assignees

• Oracle Int Corp

Inventors

• Zheng Xuezhe
• Krishnamoorthy Ashok V
• Raj Kannan

Classifications

• H01S5/026 Primary

  Monolithically integrated components, e.g. waveguides, monitoring photo-detectors, drivers (stabilisation of output H01S5/06) · CPC title

• H01S5/0228 Primary

  Electricity · mapped topic

• G02B6/42 Primary

  Coupling light guides with opto-electronic elements · CPC title

• H01S5/185

  having only horizontal cavities, e.g. horizontal cavity surface-emitting lasers [HCSEL] (comprising a photonic bandgap structure H01S5/11) · CPC title

• H01S5/0225 Primary

  Out-coupling of light · CPC title