Polarization-insensitive optical transceiver

Patent metadata

Field	Value
Publication number	US-9983359-B2
Application number	US-201715685716-A
Country	US
Kind code	B2
Filing date	Aug 24, 2017
Priority date	Jun 16, 2016
Publication date	May 29, 2018
Grant date	May 29, 2018

Abstract

An integrated circuit that includes a wavelength-filter layer stack (which may include silicon oxynitride) and an optical substrate (such as a silicon-on-insulator platform) is described. During operation, an optical signal received from an optical fiber or an optical waveguide is wavelength filtered into a set of wavelength-filter optical waveguides by an optical multiplexer/demultiplexer (such as an Echelle grating and/or an array waveguide grating) in the wavelength-filter layer stack. Then, wavelength-filtered optical signals are optically coupled to the optical substrate, where they are received using photodetectors. Alternatively, modulators in the optical substrate modulate wavelength-filtered modulated optical signals, which are then optically coupled to the set of wavelength-filter optical waveguides in the wavelength-filter layer stack. Next, the wavelength-filtered modulated optical signals are combined using the optical multiplexer/demultiplexer, and the resulting optical signal is output to the optical fiber or the optical waveguide.

First claim

What is claimed is:

1. An integrated circuit, comprising:
a wavelength-filter layer stack that includes:
a first information optical coupler that, during operation, communicates an optical signal;
a first information optical waveguide optically coupled to the first information optical coupler;
an optical multiplexer/demultiplexer optically coupled to the first information optical waveguide;
a set of wavelength-filter optical waveguides optically coupled to the optical multiplexer/demultiplexer; and
wavelength-filter optical couplers optically coupled to the set of wavelength-filter optical waveguides, wherein the wavelength-filter layer stack includes silicon oxynitride; and

an optical substrate that includes:
a buried-oxide (BOX) layer disposed on the optical substrate; and
a semiconductor layer disposed on the BOX layer, wherein the semiconductor layer includes:
an optical-fiber coupler that, during operation, communicates the optical signal with an optical fiber;
a second information optical waveguide optically coupled to the optical-fiber coupler;
a second information optical coupler optically coupled to the second information optical waveguide and vertically aligned with the wavelength-filter optical coupler, wherein, during operation, the second information optical coupler communicates the optical signal with the first information optical coupler;
vertical couplers aligned with the wavelength-filter optical couplers that, during operation, communicate components of the optical signal with the wavelength-filter optical couplers; and
a set of optical waveguides optically coupled to the vertical optical couplers;
wherein the first and second information optical waveguides and the set of wavelength-filter optical waveguides include channel optical waveguides;
wherein the set of optical waveguides includes ridge optical waveguides; and
wherein, in a region of overlap of the wavelength-filter optical couplers and the vertical optical couplers, a width of the set of wavelength-filter optical waveguides is decreased, a width of a ridge portion of the ridge optical waveguides is decreased while a width of a slab portion of the ridge optical waveguides is increased, and then, in a region of the ridge optical waveguides without the slab portion, a width of the slab portion of the ridge optical waveguides is decreased.

2. The integrated circuit of claim 1 , wherein the first information optical coupler, the second information optical coupler, the wavelength-filter optical couplers and the vertical optical couplers include one of: inverse tapers, and facet mirrors.

3. The integrated circuit of claim 1 , wherein the wavelength-filter layer stack includes a polarization-dependent-frequency-shift compensator.

4. The integrated circuit of claim 1 , wherein the optical multiplexer/demultiplexer includes one of: an Echelle grating, and an array waveguide grating.

5. The integrated circuit of claim 1 , wherein the optical substrate includes one of: photodetectors optically coupled to the set of wavelength-filter optical waveguides; and modulators optically coupled to the set of wavelength-filter optical waveguides.

6. The integrated circuit of claim 1 , wherein the integrated circuit operates without tuning of carrier wavelengths in components of the optical signal.

7. 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 wavelength-filter layer stack that includes:
a first information optical coupler that, during operation, communicates an optical signal;
a first information optical waveguide optically coupled to the first information optical coupler;
an optical multiplexer/demultiplexer optically coupled to the first information optical waveguide;
a set of wavelength-filter optical waveguides optically coupled to the optical multiplexer/demultiplexer; and
wavelength-filter optical couplers optically coupled to the set of wavelength-filter optical waveguides, wherein the wavelength-filter layer stack includes silicon oxynitride; and

an optical substrate that includes:
a buried-oxide (BOX) layer disposed on the optical substrate; and
a semiconductor layer disposed on the BOX layer, wherein the semiconductor layer includes:
an optical-fiber coupler that, during operation, communicates the optical signal with an optical fiber;
a second information optical waveguide optically coupled to the optical-fiber coupler;
a second information optical coupler optically coupled to the second information optical waveguide and vertically aligned with the wavelength-filter optical coupler, wherein, during operation, the second information optical coupler communicates the optical signal with the first information optical coupler;
vertical couplers aligned with the wavelength-filter optical couplers that, during operation, communicate components of the optical signal with the wavelength-filter optical couplers; and
a set of optical waveguides optically coupled to the vertical optical couplers;
wherein the first and second information optical waveguides and the set of wavelength-filter optical waveguides include channel optical waveguides;
wherein the set of optical waveguides includes ridge optical waveguides; and
wherein, in a region of overlap of the wavelength-filter optical couplers and the vertical optical couplers, a width of the set of wavelength-filter optical waveguides is decreased, a width of a ridge portion of the ridge optical waveguides is decreased while a width of a slab portion of the ridge optical waveguides is increased, and then, in a region of the ridge optical waveguides without the slab portion, a width of the slab portion of the ridge optical waveguides is decreased.

Assignees

• Oracle Int Corp

Inventors

• Luo Ying
• Zheng Xuezhe
• Yao Jin
• Krishnamoorthy Ashok V

Classifications

• G02B6/2938

  for multiplexing or demultiplexing, i.e. combining or separating wavelengths, e.g. 1xN, NxM · CPC title

• G02B6/122

  Basic optical elements, e.g. light-guiding paths · CPC title

• G02B2006/12097

  Ridge, rib or the like · CPC title

• G02B6/29361

  Interference filters, e.g. multilayer coatings, thin film filters, dichroic splitters or mirrors based on multilayers, WDM filters · CPC title

• G02B6/29397 Primary

  Polarisation insensitivity · CPC title