Optical Phased Array Phase Error Correction via Photodetector Feedback
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Solution Overview
Problem
Existing optical phased arrays face challenges in efficiently correcting phase errors generated during manufacturing, requiring complex and costly calibration setups and taking a long time to achieve accurate beam steering, especially as the number of phase shifters increases.
Innovation Solution
The proposed solution involves an optical phased array design that includes a light injector, splitters, phase shifters, and photodetectors to measure electrical signals and apply phase corrections without external cameras, allowing for rapid and reliable phase error correction by controlling the phase shifters based on measured signals, thereby reducing the need for complex calibration setups and significantly speeding up the correction process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional calibration setups with external cameras are used to correct phase errors, then measurement precision is improved, but device complexity and correction time increase significantly
Solution Approach 1:
The patent introduces an intermediary measurement system consisting of photodetectors and splitters that mediate between the phase shifters and the external measurement equipment. This intermediary system converts optical phase information into electrical signals that can be measured and processed, eliminating the need for complex external camera-based calibration setups while maintaining measurement precision
Solution Approach 2:
The patent replaces the mechanical/optical camera-based measurement system with an electrical measurement system using photodetectors. By converting optical phase measurements into electrical signal measurements through the photodetector array, the system achieves simpler instrumentation and faster data acquisition without sacrificing measurement accuracy
2Measurement precision
If conventional camera-based calibration methods are used, then phase error detection is achieved, but correction time increases by 15 to 500 times
Solution Approach 1:
The patent enables continuous phase error measurement and correction by having photodetectors continuously monitor the optical signals from all phase shifters simultaneously. This continuous measurement capability eliminates the sequential frame-by-frame acquisition limitation of camera-based systems, allowing for real-time feedback and immediate correction without interruption
Solution Approach 2:
The patent performs preliminary measurement of phase errors for all phase shifters simultaneously before correction is applied. The measurement system captures the state of all N phase shifters at once, allowing the control system to calculate and apply corrections to all elements in parallel, significantly reducing total correction time compared to sequential measurement and correction approaches
3Adaptability or versatility
If the number of phase shifters is increased to improve beam steering capability, then adaptability is improved, but correction complexity and time increase
Solution Approach 1:
The patent segments the measurement and correction function into independent modular units - each photodetector is independently connected to each phase shifter through splitters, creating a scalable N×N measurement matrix. This modular segmentation allows the system to handle any number of phase shifters without increasing per-element complexity, as each element has its own dedicated measurement path
Solution Approach 2:
The patent creates a universal measurement system where the same photodetector array and splitter network can measure phase errors for any number of phase shifters. The system is designed to be scalable and adaptable to different configurations, with the measurement principles and hardware architecture remaining consistent regardless of the number of elements in the phased array
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 enables phase error correction 15 to 500 times faster than conventional methods, improving the reliability and efficiency of beam steering in optical phased arrays, particularly in solid-state LiDAR applications.
Implementation Method 1
a first photodetector connected to the first splitter and provided to detect a portion of light radiated onto the antenna array
Implementation Method 2
a first splitter connected to the light injector, a first phase shifter connected to the first splitter, a plurality of waveguides connected to the first splitter
Implementation Method 3
The phase shifter provides different phase differences to each of the N channels. Optical signals with different phases in each channel are interfered through an antenna array
Implementation Method 4
Optical signals with different phases in each channel are interfered through an antenna array, and thus, become a single beam having directivity
Data Source
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AI summary
Provided is an optical phased array including a light injector, a first splitter connected to the light injector, a first phase shifter connected to the first splitter, a plurality of waveguides connected to the first splitter, portions of the plurality of waveguides being connected to the first splitter via the first phase shifter, an antenna array connected to the plurality of waveguides, a single mode filter provided in each of the plurality of waveguides, and a first photodetector connected to the first splitter and configured to detect a portion of light radiated onto the antenna array.