Optical Vector Multiplier Using Incoherent Detection
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Solution Overview
Problem
Current optical vector multiplication methods in the domain face challenges with maximizing speed and efficiency, particularly due to system losses and the difficulty in coherent addition of signals at optical frequencies, which limits their scalability and accuracy in processing large numbers of inputs.
Innovation Solution
A wavelength selective switch apparatus is used to perform optical vector multiplication by applying specific loss factors to each input signal of different wavelengths, utilizing a spatial light modulator and diffraction elements to combine the signals incoherently, minimizing system losses and enabling scalable solutions for large input sets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If spatial light modulators are used for optical vector multiplication, then the multiplication can be performed in the optical domain, but system losses increase and coherent addition becomes difficult at optical frequencies
Solution Approach 1:
The patent changes the fundamental parameter of signal combination from coherent addition to incoherent detection. By using direct detection at photodetectors, the system avoids the complexities and losses associated with maintaining coherence at optical frequencies, thereby reducing system losses while maintaining high-speed optical vector multiplication capability
Solution Approach 2:
The patent substitutes the mechanical/optical approach of coherent beam combining with an electrical detection approach. Photodetectors convert optical signals to electrical signals for detection, replacing the need for precise optical phase control and coherent addition, which reduces system complexity and energy losses
2Adaptability or versatility
If ring resonators are used for optical vector multiplication, then wavelength-division multiplexing can be implemented, but system losses increase and scalability is limited
Solution Approach 1:
The patent changes the detection parameter from coherent optical detection to incoherent electrical detection. This allows wavelength-division multiplexing to be maintained while avoiding the cumulative losses that occur when multiple resonators are cascaded, enabling better scalability to large input sets
Solution Approach 2:
The patent segments the optical vector multiplication process into independent wavelength channels, each detected separately by photodetectors. This segmentation allows wavelength-division multiplexing while avoiding the system losses associated with cascaded ring resonators, as each channel is processed independently through direct detection
3Measurement precision
If coherent addition of optical signals is performed, then vector multiplication accuracy can be maintained, but the difficulty of coherent addition at optical frequencies increases with the number of inputs
Solution Approach 1:
The patent substitutes coherent optical addition with incoherent electrical addition. Photodetectors convert optical signals to electrical signals where addition occurs in the electrical domain, which is inherently simpler and more scalable than maintaining coherence in the optical domain, especially for large numbers of inputs
Solution Approach 2:
The patent introduces photodetectors as intermediary devices that convert optical signals to electrical signals. This intermediary step allows the system to maintain vector multiplication accuracy through precise electrical detection and addition while avoiding the increasing complexity of coherent optical addition at optical frequencies
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 approach enhances the speed and efficiency of optical vector multiplication, reducing system losses and allowing for the processing of hundreds or thousands of spin variables, overcoming limitations of existing methods like spatial light modulators and ring resonators.
Implementation Method 1
one or more sets of light modulator elements, wherein within each set, each light modulator element in the set is arranged to receive the beam of light modulated with a different corresponding one of said input signals, and apply a corresponding weight from a vector of weights
Implementation Method 2
utilizing a spatial light modulator and diffraction elements to combine the signals incoherently
Implementation Method 3
one or more optical combining elements arranged, for each of said sets, to direct the weighted optical signals of the set onto the respective photosensor element and thereby produce a respective output in the form of an analogue electronic signal summing the weighted optical signals of the respective set
Data Source
AI summary
Apparatus for performing vector-by-vector multiplication in an optical domain, comprising: a plurality of light signal generators, each arranged to emit a beam of light having a different respective carrier wavelength modulated with an input signal modelling a respective variable of a vector of variables; one or more sets of light modulator elements, wherein each light modulator element in each set is arranged to receive the beam of light modulated with a different one of said input signals, and apply a corresponding weight from a vector of weights in order to produce a weighted optical signal; a respective photosensor element for each of said sets; and one or more optical combining elements arranged to direct the weighted optical signals of each set onto the respective photosensor element and thereby produce a respective output in the form of an analogue electronic signal summing the weighted optical signals of the respective set.