Systems and methods for activation functions for photonic neural networks

Patent metadata

Field	Value
Publication number	US-11460753-B2
Application number	US-201917054127-A
Country	US
Kind code	B2
Filing date	May 10, 2019
Priority date	May 10, 2018
Publication date	Oct 4, 2022
Grant date	Oct 4, 2022

Abstract

Systems and methods for activation in an optical circuit in accordance with embodiments of the invention are illustrated. One embodiment includes an optical activation circuit, wherein the circuit comprises a directional coupler, an optical-to-electrical conversion circuit, a time delay element, a nonlinear signal conditioner, and a phase shifter. The directional coupler receives an optical input and provides a first portion to the optical-to-electrical conversion circuit and a second portion to the time delay element, the time delay element provides a delayed signal to the phase shifter, and the optical-to-electrical conversion circuit converts an optical signal from the directional coupler to an electrical signal used to activate the phase shifter to shift the phase of the delayed signal.

First claim

What is claimed is:

1. An optical activation circuit, wherein the circuit comprises:
a directional coupler;
an optical-to-electrical conversion circuit;
a time delay element;
a nonlinear signal conditioner; and
a phase shifter, wherein:
the directional coupler receives an optical input and provides a first portion to the optical-to-electrical conversion circuit and a second portion to the time delay element;
the time delay element provides a delayed signal to the phase shifter; and
the optical-to-electrical conversion circuit converts an optical signal from the directional coupler to an electrical signal used to activate the phase shifter to shift the phase of the delayed signal.

2. The circuit of claim 1 , wherein the nonlinear signal conditioner performs a nonlinear transformation of a voltage from the optical-to-electrical conversion circuit.

3. The circuit of claim 2 , further comprising an element to add a static bias voltage to the electrical signal used to activate the phase shifter.

4. The circuit of claim 1 , wherein the phase shifter is embedded in an interferometer to modulate the intensity of the delayed signal.

5. The circuit of claim 4 , wherein the interferometer is a Mach-Zehnder interferometer.

6. The circuit of claim 1 , wherein the optical-to-electrical conversion circuit comprises a photodetector.

7. The circuit of claim 6 , wherein the optical-to-electrical conversion circuit further comprises a signal amplifier.

8. The circuit of claim 7 , wherein the signal amplifier is a semiconductor optical amplifier.

Assignees

• Univ Leland Stanford Junior

Inventors

• Hughes Tyler William
• Minkov Momchil
• Williamson Ian
• Fan Shanhui

Classifications

• G06V10/94

  Hardware or software architectures specially adapted for image or video understanding · CPC title

• G06V10/955

  using specific electronic processors · CPC title

• G06V10/454

  Integrating the filters into a hierarchical structure, e.g. convolutional neural networks [CNN] · CPC title

• G06N3/048

  Activation functions · CPC title

• G06N3/0675

  using electro-optical, acousto-optical or opto-electronic means · CPC title