Optical Pattern Recognition Wavelength Conversion Stability
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Solution Overview
Problem
Existing passive optical correlation techniques face challenges in scaling to process large numbers of header bits due to wavelength stability issues and inability to distinguish arbitrary on-off-keyed (OOK) data bits, limiting the number of header patterns that can be used.
Innovation Solution
The solution involves an apparatus and method that includes a laser, converter, and correlator to perform pattern recognition on data-modulated optical signals by wavelength converting the input signal and correlating it with a specified pattern, using a continuous wave laser to ensure stability and converting OOK signals to BPSK format for improved recognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If passive optical correlation techniques are used to process a large number of header bits, then the routing capacity increases, but the sensitivity to wavelength variations worsens
Solution Approach 1:
The patent introduces a wavelength conversion stage as an intermediary between the input optical signal and the passive correlator. This converter translates the input wavelength to a stable reference wavelength, mediating the interaction between the variable input signal and the wavelength-sensitive correlator, thereby protecting the correlator from wavelength variations while maintaining high routing capacity
Solution Approach 2:
The patent changes the wavelength parameter of the optical signal through active conversion rather than relying on passive filtering. By actively controlling the wavelength conversion process using a stable reference laser, the system can process more header bits through the correlator while maintaining wavelength stability, thus resolving the contradiction between routing capacity and wavelength sensitivity
2Device complexity
If passive optical filters are used for pattern recognition, then the device complexity is reduced, but the ability to distinguish arbitrary OOK data bits is lost
Solution Approach 1:
The patent replaces passive optical filtering (analog/mechanical approach) with active wavelength conversion followed by correlation processing. This substitution enables digital-like precise pattern matching while maintaining the simplicity of optical processing, allowing the system to distinguish arbitrary OOK patterns without significantly increasing device complexity
Solution Approach 2:
The patent segments the pattern recognition function into two distinct stages: wavelength conversion (signal preparation) and correlation processing (pattern matching). This segmentation allows each stage to be optimized independently - the converter handles wavelength stabilization while the correlator handles pattern recognition, achieving both simplicity and versatility
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 reduces sensitivity to wavelength variations, enabling effective recognition of a wider range of header patterns, including arbitrary OOK patterns, and enhances the scalability of optical data routing systems.
Implementation Method 1
The converter receives the laser signal and the input signal and wavelength converts the input signal into a data-modulated converted optical signal having the second wavelength
Data Source
AI summary
In exemplary embodiments, all-optical pattern recognition for an optical input signal is achieved by wavelength-converting the input signal and then passively correlating the wavelength-converted signal based on a specified data pattern. By performing wavelength conversion using a CW laser signal having wavelength stability greater than that of the input signal, errors resulting from wavelength sensitivity of the passive correlator can be reduced. By performing both wavelength conversion and OOK-to-BPSK format conversion prior to the passive correlation, limitations in the number of available OOK patterns can be avoided. By performing the passive correlation in a bi-directional manner, feedback signal can be generated to control the operations of the passive correlator and/or the laser signal source(s).