Optical Waveform Phase Distortion Compensation
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Solution Overview
Problem
Conventional methods for synthesizing high bandwidth, single-sideband, linear frequency modulated optical waveforms are complicated by deterministic waveform distortions introduced by RF and optical components, particularly in the presence of laser phase noise.
Innovation Solution
A method and apparatus that characterize and compensate for deterministic phase nonlinearities and distortions by mixing a modulated optical signal with a constant frequency optical signal, optically heterodyning the output, and using a processor to compare the resulting radio frequency waveform with a known theoretical phase history to measure distortion characteristics, employing Legendre Polynomials for analysis and compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods are used to synthesize high bandwidth optical waveforms, then the synthesis process can be completed, but deterministic waveform distortions are introduced by RF and optical components
Solution Approach 1:
The patent applies preliminary action by measuring the distortion characteristics of RF and optical components before waveform synthesis, then pre-compensating for these distortions in the synthesized waveform. The system characterizes deterministic phase nonlinearities in advance and applies correction factors to eliminate their harmful effects on the final waveform accuracy.
2Productivity
If laser phase noise is present during waveform synthesis, then the synthesis process can proceed, but the deterministic distortions become more difficult to characterize and minimize
Solution Approach 1:
The patent extracts deterministic phase distortion components from the total phase noise by using heterodyne detection and spectral analysis. The system separates the deterministic distortions (which can be measured and corrected) from the random laser phase noise (which cannot be corrected but can be filtered out), allowing accurate characterization of distortions even in the presence of laser noise.
3Ease of operation
If RF and optical components are used in the synthesis procedure, then the waveform can be generated, but gain, phase delay, nonlinearity and other distortion phenomena are introduced
Solution Approach 1:
The patent implements feedback by measuring the actual distortion characteristics of RF and optical components using heterodyne detection, then using these measurements to adjust and pre-compensate the synthesized waveform. The system continuously characterizes component distortions and applies correction factors to maintain high waveform fidelity despite the presence of distorting components.
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 effectively minimizes and eliminates deterministic phase nonlinearities and distortions, resulting in a waveform that is substantially free of phase errors and distortions, enhancing the fidelity of ultra-wide bandwidth optical waveforms.
Implementation Method 1
optically heterodyning the mixed signal output from the optical coupler in a detector to produce a radio frequency waveform
Data Source
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AI summary
In accordance with various aspects of the disclosure, a method, an apparatus and a system for characterizing and compensating for deterministic phase nonlinearities and distortion inherent in radio frequency and optical components utilized to synthesize a single sideband suppressed carrier optical waveform in the presence of random phase noise generated by an optical carrier source is disclosed. The method comprises mixing a modulated optical signal with a continuous wave optical signal in an optical coupler; optically heterodyning the mixed signal output from the optical coupler in a detector to produce a radio frequency waveform; and analyzing the produced radio frequency waveform in a processor based on a phase history of a preselected continuous wave signal to measure distortion characteristics of the radio frequency modulated optical signal.