# US 11,442,228 B2 · System for phase-based photonic computing

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- Number: US 11,442,228 B2
- Document ID: US11442228B2
- Status: Granted
- Kind: B2
- Application number: 16/848,429
- Filed: 2020-04-14
- Published: 2020-09-10
- Granted: 2022-09-13
- Earliest claimed: 2018-11-08
- Assignees: Luminous Computing, Inc.
- Applicants: Luminous Computing, Inc.
- Inventors: Mitchell A. Nahmias
- Web page: https://patentgrep.com/patent/US11442228B2

## CPC

- G02B 6/29355: {Cascade arrangement of interferometers}
- G06E 3/005: {using electro-optical or opto-electronic means}
- G02B 6/4215: {the intermediate optical elements being wavelength selective optical elements, e.g. variable wavelength optical modules or wavelength lockers (G02B6/4246 takes precedence)}
- G06E 3/008: {Matrix or vector computation}
- H04J 14/02: Wavelength-division multiplex systems
- H04B 10/70: Photonic quantum communication
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G06E: OPTICAL COMPUTING DEVICES (digital storage using optical elements G11C13/04)
- H04J: MULTIPLEX COMMUNICATION (transmission in general H04B; peculiar to transmission of digital information H04L5/00; systems for the simultaneous or sequential transmission of more than one television signal H04N7/08; in exchanges H04Q11/00; stereophonic systems H04S)
- H04B: TRANSMISSION

## Abstract

A system for photonic computing, preferably including an input module, computation module, and/or control module, wherein the computation module preferably includes one or more filter banks and/or detectors. A photonic filter bank system, preferably including two waveguides and a plurality of optical filters optically coupled to one or more of the waveguides. A method for photonic computing, preferably including controlling a computation module, controlling an input module, and/or receiving outputs from the computation module.

## Claims

### Claim 1

A system comprising:
a spectral filter bank comprising:
a first waveguide comprising a first input end and a first output end;
a second waveguide comprising a second input end and a second output end;
a first optical filter associated with a first optical characteristic, the first optical filter optically coupled to the first waveguide between the first input end and the first output end;
a second optical filter associated with a second optical characteristic different from the first optical characteristic, the second optical filter optically coupled to the first waveguide between the first input end and the first output end; and
an optical coupler, optically coupled to the first output end and the second output end, the optical coupler configured to:
receive a first optical signal at the first output end;
receive a second optical signal at the second output end;
generate an optical interference signal by optically coupling the first and second optical signals; and
provide the optical interference signal at a coupler output;
a third waveguide comprising a third input end, a third output end, and a third coupling region between the third input end and the third output end;
a fourth waveguide comprising a fourth input end, a fourth output end, and a fourth coupling region between the fourth input end and the fourth output end;
a third optical filter associated with the first optical characteristic, the third optical filter optically coupled to the third waveguide between the third input end and the third coupling region;
a fourth optical filter associated with the second optical characteristic, the fourth optical filter optically coupled to the third waveguide between the third input end and the third coupling region;
a second optical coupler that optically couples the third coupling region and the fourth coupling region; and
an optical splitter comprising a splitter input, a first splitter output, a second splitter output, a third splitter output, and a fourth splitter output, wherein:
the optical splitter is configured to:
split an optical input signal, received at the splitter input, into a first optical output signal, a second optical output signal, a third optical output signal, and a fourth optical output signal;
provide the first optical output signal at the first splitter output;
provide the second optical output signal at the second splitter output;
provide the third optical output signal at the third splitter output; and
provide the fourth optical output signal at the fourth splitter output;
the first splitter output is optically coupled to the first input end;
the second splitter output is optically coupled to the second input end;
the third splitter output is optically coupled to the third input end; and
the fourth splitter output is optically coupled to the fourth input end.

### Claim 2 (depends on 1)

The system of claim 1, further comprising an optical detector optically coupled to the coupler output.

### Claim 3 (depends on 2)

The system of claim 2, wherein the optical detector comprises a photodiode.

### Claim 4 (depends on 2)

The system of claim 2, wherein:
the optical coupler is further configured to:
concurrent with generating the optical interference signal, generate a second optical interference signal; and
provide the second optical interference signal at a second coupler output; and
the system further comprises a second optical detector optically coupled to the second coupler output.

### Claim 5 (depends on 1)

The system of claim 1, wherein:
the first optical characteristic is a first optical wavelength;
the second optical characteristic is a second optical wavelength;
the first optical filter comprises a first wavelength-selective filter; and
the second optical filter comprises a second wavelength-selective filter.

### Claim 6 (depends on 5)

The system of claim 5, wherein:
based on a first control signal, the first wavelength-selective filter is configured to phase-shift a first portion of light within the first waveguide, the first portion having the first optical wavelength; and
based on a second control signal, the second wavelength-selective filter is configured to phase-shift a second portion of light within the first waveguide, the second portion having the second optical wavelength.