Photonic filter bank system and method of use

Patent metadata

Field	Value
Publication number	US-10670860-B2
Application number	US-201916374991-A
Country	US
Kind code	B2
Filing date	Apr 4, 2019
Priority date	Apr 30, 2018
Publication date	Jun 2, 2020
Grant date	Jun 2, 2020

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 arranged between 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.

First claim

We claim:

1. A method for optical computation comprising:
throughout a time period, controlling a filter bank based on a plurality of weights, comprising:
based on a first weight of the plurality, determining a first control signal;
based on a second weight of the plurality, determining a second control signal;
providing the first control signal to a first optical filter of the filter bank, wherein the first optical filter is associated with a first optical characteristic; and
providing the second control signal to a second optical filter of the filter bank, wherein the second optical filter is associated with a second optical characteristic different from the first optical characteristic;

during the time period, receiving an optical input signal at an input waveguide of the filter bank, wherein the optical input signal comprises:
a first portion having the first optical characteristic; and
a second portion having the second optical characteristic; and

during the time period, in response to receiving the optical input signal at the input waveguide:
at the first optical filter, based on the first control signal, coupling a first signal subportion of the first portion from the input waveguide to an output waveguide of the filter bank;
at the second optical filter, based on the second control signal, coupling a second signal subportion of the second portion from the input waveguide to the output waveguide;
at the second optical filter, coupling a first leakage subportion of the first portion from the input waveguide to the output waveguide; and
at the output waveguide, outputting the first signal subportion, the second signal subportion, and the first leakage subportion, wherein the first signal subportion is phase-shifted with respect to the first leakage subportion.

2. The method 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.

3. The method of claim 2 , wherein:
the first wavelength-selective filter comprises a first microresonator;
the second wavelength-selective filter comprises a second microresonator;
providing the first control signal to the first optical filter alters a first resonance wavelength of the first microresonator; and
providing the second control signal to second first optical filter alters a second resonance wavelength of the second microresonator.

4. The method of claim 3 , wherein:
the first wavelength-selective filter is a first even-pole filter; and
the second wavelength-selective filter is a second even-pole filter.

5. The method of claim 1 , wherein the first signal subportion and the first leakage subportion define a phase difference, wherein a magnitude of the phase difference is between π/4 radians and 3π/4 radians.

6. The method of claim 5 , wherein the phase difference is substantially equal to ±π/2 radians.

7. The method of claim 1 , further comprising:
throughout a second time period after the time period, controlling the filter bank based on a second plurality of weights, comprising:
based on a third weight of the second plurality, determining a third control signal;
based on a fourth weight of the second plurality, determining a fourth control signal;
providing the third control signal to the first optical filter; and
providing the fourth control signal to the second optical filter;

during the second time period, receiving a second optical input signal at the input waveguide, wherein the second optical input comprises:
a third portion having the first optical characteristic; and
a fourth portion having the second optical characteristic; and

during the second time period, in response to receiving the second optical input signal at the input waveguide:
at the first optical filter, based on the third control signal, coupling a third signal subportion of the third portion from the input waveguide to the output waveguide;
at the second optical filter, based on the fourth control signal, coupling a fourth signal subportion of the fourth portion from the input waveguide to the output waveguide;
at the second optical filter, coupling a third leakage subportion of the third portion from the input waveguide to the output waveguide; and
at the output waveguide, outputting the third signal subportion, the fourth signal subportion, and the third leakage subportion, wherein the third signal subportion is phase-shifted with respect to the third leakage subportion by a phase difference;

wherein the first signal subportion is phase-shifted with respect to the first leakage subportion substantially by the phase difference.

8. The method of claim 7 , wherein:
a first amplitude ratio of the first signal subportion to the first portion is substantially equal to the first weight; and
a third amplitude ratio of the third signal subportion to the third portion is substantially equal to the third weight.

9. The method of claim 1 , wherein:
the filter bank further comprises a third optical filter associated with a third optical characteristic different from the first and second optical characteristics;
the optical input signal further comprises a third portion having the third optical characteristic;
controlling the filter bank based on the plurality of weights further comprises:
based on a third weight of the plurality, determining a third control signal; and
providing the third control signal to the third optical filter; and

the method further comprises, during the time period, in response to receiving the optical input signal at the input waveguide:
at the third optical filter, based on the third control signal, coupling a third signal subportion of the third portion from the input waveguide to the output waveguide;
at the third optical filter, coupling a second leakage subportion of the second portion from the input waveguide to the output waveguide; and
at the output waveguide, outputting the third signal subportion and the second leakage subportion, wherein the second signal subportion is phase-shifted with respect to the second leakage subportion.

10. The method of claim 9 , further comprising, during the time period, in response to receiving the optical input signal at the input waveguide:
at the first optical filter, coupling a fourth leakage subportion of the second portion from the input waveguide to the output waveguide; and
at the output waveguide, outputting the fourth leakage subportion, wherein the second signal subportion is phase-shifted with respect to the fourth leakage subportion.

11. The method of claim 1 , wherein:
the input waveguide defines a first propagation vector, wherein the optical input signal propagates along the first propagation vector;
the output waveguide defines a second propagation vector, wherein the first signal subportion and the second signal subportion propagate along the second propagation vector; and
a dot product of the first and second propagation vectors is greater than zero.

12. The method of claim 1 , wherein:
the first optical filter couples the first signal subportion from a first point of the input waveguide to a second point of the output waveguide;
the second optical filter couples the second signal subportion and the first leakage subportion from a third point of the input waveguide to a fourth point of the output waveguide;
the first signal subportion propagates along a first input waveguide section from the third point to the first point;
the second signal subpo

Assignees

• Univ Princeton

Inventors

• Tait Alexander N
• Wu Allie X
• De Lima Thomas Ferreira
• Nahmias Mitchell A
• Shastri Bhavin J
• Prucnal Paul R

Classifications

• G02F1/225 Primary

  in an optical waveguide structure · CPC title

• G02B27/0012 Primary

  Optical design, e.g. procedures, algorithms, optimisation routines · CPC title