Optical Circulator Mitigates Lidar Backscatter Saturation
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Solution Overview
Problem
LIDAR systems face issues with backscatter, where internally reflected light causes receivers to enter a temporary saturation and blind period, and partial signal loss due to polarization state interactions, leading to incomplete environmental data.
Innovation Solution
The use of an optical circulator in the LIDAR optics system replaces traditional polarizing beam splitters, spatially separating outbound and return light paths to mitigate backscatter and capture multiple polarization states, ensuring complete signal reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional polarizing beam splitters are used in LIDAR optics, then the system structure is simple, but backscatter causes receiver saturation and signal loss occurs due to polarization state interactions
Solution Approach 1:
The optical system is segmented into separate outbound and return light paths using an optical circulator. The circulator divides the optical path into distinct segments: one for emitting light outward and another for receiving return light, preventing backscatter from affecting the receiver while maintaining complete signal reception capability.
Solution Approach 2:
An optical circulator is introduced as an intermediary device between the emitter and receiver. This mediator spatially separates the outbound and return light paths, allowing the system to capture all return light including multiple polarization states while preventing internally reflected light from causing receiver saturation.
2Reliability
If optical circulator is used to spatially separate light paths, then backscatter is mitigated and signal reception is enhanced, but device complexity increases
Solution Approach 1:
The optical circulator performs multiple functions simultaneously: it separates outbound and return light paths, prevents backscatter from reaching the receiver, captures all return light including multiple polarization states, and maintains system compactness. This multi-functionality justifies the increased device complexity by delivering comprehensive performance improvements.
3Loss of information
If polarizing beam splitters are used, then device complexity is low, but signal reception is incomplete due to loss of polarization states
Solution Approach 1:
The optical circulator extracts and separates different polarization states of return light into distinct paths, allowing each polarization state to be captured independently. This extraction process prevents loss of polarization information while maintaining a relatively simple overall system structure compared to traditional polarizing beam splitter configurations.
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 solution prevents premature receiver saturation, enhances signal reception by capturing all return light, and increases the extinction ratio between emitted and return light signals, providing more accurate environmental data.
Implementation Method 1
backscatter, where internally reflected light causes receivers to enter a temporary saturation
Implementation Method 2
LIDAR systems may only be able to receive as little as half of the emitted light signal back at the receiver devices due to loss of polarization states
Data Source
AI summary
Systems and methods are provided herein for light backscattering mitigation in LIDAR systems in some embodiments, an example method may include emitting, by an emitter, an outbound light signal. The example method may also include receiving, by a circulator disposed a first path of the outbound light signal and a second path of a return light signal, the outbound light signal from the emitter. The example method may also include outputting the outbound light signal. The example method may also include receiving, by the circulator, the return light signal from an environment, the return light signal comprising a first portion in a first polarization state and a second portion in a second polarization state. The example method may also include providing, by the circulator and on a third path, the first portion of the return light signal to a first element.