LiDAR Optical Circulator Polarization Diversity Architecture
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Solution Overview
Problem
Conventional LiDAR systems are inefficient in collecting and mixing all polarization states of light scattered from targets, leading to reduced coherently mixed heterodyne signals and lower signal-to-noise ratios.
Innovation Solution
A LiDAR system with a polarization-diverse architecture that utilizes combinations of polarizers, wave-retardation optics, and magneto-optics, such as Faraday rotators, to collect and mix all possible polarization states of the returned target signal with a local oscillator signal, enhancing the signal-to-noise ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional LiDAR systems use single polarization state collection, then the system structure is simple, but the light collection efficiency is reduced
Solution Approach 1:
The patent segments the polarization states into multiple independent detection channels. By dividing the single detection path into multiple polarization-specific channels (e.g., horizontal, vertical, circular polarizations), the system can collect and process each polarization state separately, thereby capturing all scattered light regardless of its polarization state and improving overall light collection efficiency.
Solution Approach 2:
The patent implements a polarization-diverse detection system that can handle multiple polarization states simultaneously through a single integrated architecture. The system uses polarization beam splitters and multiple photodetectors to create a universal detection capability that processes all polarization states of scattered light, making the LiDAR system effective for both polarized and unpolarized target returns.
2Device complexity
If conventional LiDAR systems collect limited polarization states, then the system complexity is low, but the heterodyne signal strength is reduced
Solution Approach 1:
The patent merges multiple polarization detection channels into a single coherent detection system. By combining the signals from different polarization channels through optical mixing with a local oscillator, the system achieves enhanced heterodyne signal strength that incorporates contributions from all scattered light polarization states, thereby improving the overall signal power.
Solution Approach 2:
The patent introduces a local oscillator as an intermediary to facilitate coherent mixing with the scattered light from multiple polarization channels. This intermediary enables the system to maintain phase information and achieve constructive interference of signals from different polarization states, thereby enhancing the heterodyne signal strength while managing system complexity.
3Device complexity
If conventional LiDAR systems use single polarization detection, then the optical path is simple, but the signal-to-noise ratio is lower
Solution Approach 1:
The patent segments the optical detection path into multiple polarization-specific channels using polarization beam splitters and wave plates. Each channel is optimized for detecting a specific polarization state, allowing the system to maximize the signal collection from each channel while minimizing losses, thereby improving the overall signal-to-noise ratio despite increased optical path complexity.
Solution Approach 2:
The patent changes the detection parameter from single polarization state to multi-polarization state detection. By adjusting the polarization optics (wave plates, polarizers) in each channel to match the expected polarization states of scattered light, the system optimizes the signal collection efficiency and enhances the signal-to-noise ratio through coherent detection of multiple polarization 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 improves the collection and mixing efficiency of the scattered target signal, resulting in enhanced signal-to-noise ratios and improved detection sensitivity for range and velocity profiling.
Implementation Method 1
an optical circulator to receive the optical beam and transmit the optical beam to a target, to receive a target return signal from the target
Implementation Method 2
magneto-optics such as Faraday rotators
Implementation Method 3
one or more photodetectors (PDs) to mix the target return signal with the LO signal
Data Source
AI summary
A light detection and ranging (LiDAR) system according to the present disclosure comprises an optical circulator and one or more photodetectors (PDs). The optical circulator is to transmit the target return signal to the one or more PDs, where the one or more PDs are to mix the target return signal with a local oscillator (LO) signal to generate a signal to extract information of the target.