OPA Phase Shifter Dithering for Wavefront Error Compensation
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Solution Overview
Problem
Optical phased arrays (OPAs) in wireless communication systems face challenges in dynamically adjusting phase shifters to counteract static and dynamic variables such as path length mismatch, optical aberrations, and atmospheric turbulence, leading to reduced power and intensity of optical communications beams.
Innovation Solution
Implementing frequency-division (FD) and time-division (TD) mode dithering techniques with orthogonal sets of functions to adjust phase shifters, using dithering to inject small perturbations at subsets of phase shifters, optimizing phase shifts for improved power and intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If phase shifters are adjusted to counteract path length mismatch, optical aberrations, and atmospheric turbulence, then beam power and intensity are improved, but system complexity increases due to the need for dynamic adjustment mechanisms
Solution Approach 1:
The patent segments the phase shifter array into multiple subsets that can be independently adjusted. Each subset is controlled separately to compensate for specific spatial variations in path length mismatch, optical aberrations, and atmospheric turbulence. This segmentation allows targeted correction without requiring complex global control mechanisms.
Solution Approach 2:
The patent implements periodic dithering signals at different frequencies to dynamically adjust phase shifters. By applying periodic perturbations and measuring the resulting beam power variations, the system identifies optimal phase corrections. This periodic action enables continuous adaptation to changing environmental conditions without requiring complex real-time calculation systems.
2Measurement precision
If dithering techniques are used to optimize phase shifts, then measurement precision of beam power is improved, but loss of time occurs during the dithering and correction process
Solution Approach 1:
The patent uses periodic dithering signals at distinct frequencies to modulate phase shifters. By measuring beam power at these specific frequencies, the system can precisely determine the effect of each phase shifter adjustment. The periodic nature allows for frequency-domain analysis that separates the effects of different phase shifters, improving measurement precision while maintaining efficient adjustment timing.
Solution Approach 2:
The patent applies preliminary dithering perturbations before final phase correction. By first applying small periodic perturbations to each phase shifter subset and measuring the response, the system pre-characterizes the beam power relationship. This preliminary action enables faster final correction without requiring extensive real-time optimization, reducing overall adjustment time.
3Adaptability or versatility
If frequency-division and time-division mode dithering are implemented, then adaptability to environmental variables is improved, but device complexity increases due to multiple dithering modes
Solution Approach 1:
The patent divides phase shifters into multiple subsets that can be independently dithered using different frequencies and timing schemes. This segmentation enables frequency-division multiplexing where each subset is assigned a unique dither frequency, allowing simultaneous independent control of multiple phase shifter groups without cross-interference. The segmentation approach simplifies the control architecture by creating modular, independently controllable units.
Solution Approach 2:
The patent implements both frequency-division and time-division dithering using periodic signals. In frequency-division mode, different phase shifter subsets are dithered at different frequencies simultaneously. In time-division mode, subsets are dithered sequentially with periodic timing. These periodic approaches provide robust adaptability to environmental variables while maintaining relatively simple control logic based on standard signal modulation techniques.
Data Source
AI summary
Aspects of the disclosure provide a method of adjusting a plurality of phase shifters of an OPA. The method may include identifying, by one or more processors, one or more first subsets of phase shifters of the plurality of phase shifters based on an orthogonal set of functions; performing, by the one or more processors, one or more first dithers on the one or more first subsets of phase shifters of the plurality of phase shifters using one or more first frequencies of a predetermined set of frequencies; determining, by the one or more processors, one or more first corrections based on a first power output of the OPA resulting from the one or more first dithers; and adjusting, by the one or more processors, the one or more first subsets using the one or more first corrections, the adjustment resulting in a first set of corrected phase shifter values.