Photonic Circuit Optical Convolution Using Discrete Fractional Fourier Transform

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Solution Overview

Problem

The on-chip realization of a convolution operator in the Fourier domain is challenging due to the lack of a compact integrated discrete Fourier transform (DFT) unit, and existing optical convolution implementations are hindered by the use of bulky lenses and pre-manufactured convolution layers, leading to issues with noise, space limitations, and scalability.

Innovation Solution

A photonic circuit architecture that performs optical convolution processing using a discrete Fractional Fourier transform (DFrFT) without the need for lenses, incorporating a first waveguide lattice for DFrFT operation, a programmable modular array of tunable phase shifters for point-wise product, and a second waveguide lattice for inverse DFrFT operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If bulky lenses and pre-manufactured convolution layers are used in optical convolution implementations, then convolution operations can be performed, but device size increases and space limitations are exacerbated

Engineering Contradiction:

Improveconvolution operation capabilityVSAvoiddevice size

Core Design Contradiction:

Ease of manufactureVSVolume of moving object

Solution Approach 1:

The patent extracts and removes the bulky lenses from the optical convolution system, replacing them with an integrated photonic circuit implementation. This extraction eliminates the primary source of device size increase while maintaining the convolution operation capability through on-chip waveguide-based optical processing.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent substitutes the mechanical/optical lens system with an integrated photonic circuit system using waveguides. This replacement transitions from a bulk optical mechanical system to a compact integrated circuit implementation, dramatically reducing device volume while preserving convolution functionality.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If pre-manufactured convolution layers are used, then convolution filtering can be performed, but noise and space limitations increase

Engineering Contradiction:

Improveconvolution filtering capabilityVSAvoidnoise

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent implements dynamically reconfigurable convolution layers using programmable phase shifters within the integrated photonic circuit. This allows the system to adapt and optimize filtering operations in real-time, reducing noise through dynamic adjustment rather than relying on fixed pre-manufactured layers that are more susceptible to manufacturing noise and limitations.

Inventive Principle:

Principle #15Dynamics

3Ease of manufacture

If bulky lenses are used in optical convolution, then Fourier domain processing can be achieved, but scalability is reduced

Engineering Contradiction:

ImproveFourier domain processing capabilityVSAvoidscalability

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The integrated photonic circuit implements a universal Fourier domain processing platform that can perform various convolution and filtering operations through programmable control. This multi-functional approach enables the system to scale to different applications and configurations without requiring additional bulky optical components, thereby improving scalability while maintaining Fourier domain processing capability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution enables efficient on-chip optical convolution processing, reducing device size and overcoming noise and space limitations, while maintaining the effectiveness of convolution operations for signal processing tasks.

Implementation Method 1

a first waveguide lattice having a first length for providing a discrete fractional Fourier transform operation on the input optical signal

Methodology Applied

Scientific EffectOptical propagation: Waveguide (optics)

Implementation Method 2

a programmable modular array of tunable phase shifters for providing the fractional Fourier transform of the kernel and performing a point-wise product on the previously transformed input optical signal

Methodology Applied

Scientific EffectPhase modulation: Phase Modulation

Implementation Method 3

a second wavelength lattice having a second length for providing an inverse discrete fractional Fourier transform operation on the previous processed optical signal

Methodology Applied

Scientific EffectOptical propagation: Waveguide (optics)

Data Source

PatentUS20250148048A1Method and device for optical convolution

Publication Date: 2025.05.08 RES FOUND THE CITY UNIV OF NEW YORK

AI summary

A photonic circuit comprises a first waveguide lattice having a first length for providing a discrete fractional Fourier transform operation on the input optical signal; a programmable modular array of tunable phase shifters for providing the fractional Fourier transform of the kernel and performing a point-wise product on the previously transformed input optical signal; a second wavelength lattice having a second length for providing an inverse discrete fractional Fourier transform operation on the previous processed optical signal; and a processor that determines a convolved output of the input signal and the convolution kernel.