Integrated Optic Vector-Matrix Multiplier Using WDM
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Solution Overview
Problem
Current digital computers are limited in performing high-speed vector-matrix multiplication, which is essential for computationally intensive applications like eigenmode calculations and image processing, due to inefficiencies in existing optical vector-matrix multipliers that suffer from bulkiness, manufacturing difficulties, high costs, cross-talk, and poor signal quality.
Innovation Solution
An integrated optic vector-matrix multiplier utilizing wavelength-division-multiplexing (WDM) technology and semiconductor microfabrication to create a compact device that minimizes cross-talk and efficiently allocates optical bandwidth, allowing for precise representation and operation with both electrical and optical inputs and outputs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If free-space optical signal processing approaches are used for vector-matrix multiplication, then optical bandwidth can be utilized, but the resulting processors become cumbersome and large in size
Solution Approach 1:
The patent replaces free-space optical mechanical systems with integrated photonic circuits that use guided wave optics. This substitution eliminates the need for bulky free-space optical components while maintaining optical bandwidth utilization, achieving compact integration of vector-matrix multiplication functionality.
Solution Approach 2:
The invention changes the operational parameters by transitioning from free-space propagation to guided wave propagation in integrated photonic circuits. This parameter change enables compact device geometry while preserving the optical bandwidth utilization needed for high-speed computation.
2Productivity
If free-space optical signal processing approaches are used, then optical computation can be performed, but manufacturing process becomes difficult to control
Solution Approach 1:
The patent replaces difficult-to-control free-space optical manufacturing with standardized integrated photonic circuit fabrication processes. These semiconductor-compatible processes enable precise control of optical paths and components, maintaining high computation speed while dramatically improving manufacturing controllability.
Solution Approach 2:
The invention employs universal integrated photonic circuit platforms that can be manufactured using standard semiconductor fabrication processes. This universality enables consistent, controllable manufacturing while supporting various computational functions through programmable optical components.
3Adaptability or versatility
If spatial light modulators are used in free-space optical systems, then matrix information can be encoded, but exotic electro-optical materials are required which are expensive and have poor light transmission quality
Solution Approach 1:
The patent replaces exotic electro-optical materials with standard semiconductor materials used in integrated photonic circuits. This substitution maintains the ability to encode matrix information through optical modulation while eliminating the need for expensive, hard-to-manufacture materials, improving both cost and light transmission quality.
Solution Approach 2:
The invention changes the material parameter from exotic electro-optical materials to standard semiconductor materials. This parameter change preserves matrix encoding capability through integrated optical modulators while dramatically improving manufacturability, cost, and optical transmission properties.
4Productivity
If free-space optical signal processing is used, then optical vector-matrix multiplication can be performed, but significant cross-talk and poor signal quality occur
Solution Approach 1:
The patent replaces free-space optical propagation with guided wave propagation in integrated photonic circuits. This substitution eliminates cross-talk between adjacent optical paths and maintains signal quality over long distances, enabling reliable high-speed vector-matrix multiplication.
Solution Approach 2:
The invention implements localized optical confinement in waveguides, ensuring that optical energy remains confined to specific transmission paths. This local quality control prevents cross-talk between adjacent channels while maintaining high signal quality, enabling reliable parallel computation.
5Productivity
If free-space optical signal processing approaches are used, then optical computation can be achieved, but uniform illumination of spatial light modulators is difficult
Solution Approach 1:
The patent replaces the difficult task of achieving uniform illumination in free-space optical systems with integrated waveguide-based optical paths. This substitution inherently provides uniform light distribution through the waveguide mode structure, eliminating illumination non-uniformity issues while maintaining high computation speed.
6Use of energy by moving object
If free-space optical signal processing is used, then optical vector-matrix multiplication can be performed, but there is inefficient use of available optical bandwidth
Solution Approach 1:
The patent replaces free-space optical processing with integrated photonic circuits that enable more efficient bandwidth utilization. The guided wave structure allows for better spectral management and reduced loss, improving the efficiency of optical bandwidth usage for vector-matrix multiplication operations.
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
The solution enables high-speed vector-matrix multiplication with improved bit-error rates and performance, capable of processing large datasets in real-time, overcoming the limitations of traditional digital computers.
Implementation Method 1
an optical multiplexer to receive a plurality of N different wavelengths of light corresponding to a number N of rows in the vector and to combine the plurality of N different wavelengths of light into an input wavelength-division-multiplexed (WDM) light stream
Implementation Method 2
An optical splitter receives the input WDM light stream from the optical multiplexer and splits the input WDM light stream into a plurality of M light streamlets, with each light streamlet being guided out of the optical splitter into a transfer waveguide
Implementation Method 3
each optical amplitude modulator in each of the M rows being coupled to one of the transfer waveguides to receive one of the N different wavelengths of light from the light streamlet in that transfer waveguide and to amplitude modulate that wavelength of light for a second time in response to an input signal which represents a column element bji of the matrix
Implementation Method 4
A plurality of M output waveguides are coupled to each optical amplitude modulator located in one of the M rows to receive each of the N different wavelengths of light from that row which have been amplitude-modulated for the second time and to form therefrom an output WDM light stream
Data Source
AI summary
A vector-matrix multiplier is disclosed which uses N different wavelengths of light that are modulated with amplitudes representing elements of an N×1 vector and combined to form an input wavelength-division multiplexed (WDM) light stream. The input WDM light stream is split into N streamlets from which each wavelength of the light is individually coupled out and modulated for a second time using an input signal representing elements of an M×N matrix, and is then coupled into an output waveguide for each streamlet to form an output WDM light stream which is detected to generate a product of the vector and matrix. The vector-matrix multiplier can be formed as an integrated optical circuit using either waveguide amplitude modulators or ring resonator amplitude modulators.