LIDAR Pixel Active Polarization Control for Speckle-Limited FMCW Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current Frequency Modulated Continuous Wave (FMCW) LIDAR systems face challenges in increasing the accuracy of range and velocity measurements due to speckle patterns and broadened signal spectra when scanning diffuse surfaces, which affect the power coupling and signal quality.
Innovation Solution
The implementation of a LIDAR system with active polarization control using a dual-polarization grating coupler and phase shifters to manipulate light into orthogonal polarization orientations, enhancing signal processing and coupling efficiency by controlling the phase and amplitude of light in coherent pixels, thereby improving signal quality and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If FMCW LIDAR scans diffuse surfaces, then environmental sensing capability is improved, but signal quality deteriorates due to speckle patterns and broadened signal spectra
Solution Approach 1:
The patent changes the polarization state parameter of the light beam by using a polarization controller to adjust the polarization orientation. This allows the system to adapt to different surface characteristics and reduce speckle patterns caused by scanning diffuse surfaces, thereby maintaining signal quality while preserving environmental sensing capability
Solution Approach 2:
The patent introduces dynamic polarization control where the polarization state can be actively adjusted during operation. The polarization controller dynamically modifies the polarization orientation to optimize signal quality for different scanning conditions and surface types, resolving the contradiction between versatility and measurement precision
2Measurement precision
If active polarization control is implemented, then signal level and measurement accuracy are improved, but device complexity increases due to additional components
Solution Approach 1:
The patent integrates the polarization controller into the existing LIDAR system architecture, making it a multi-functional component that serves both signal optimization and adaptation to different surfaces. This universal approach improves measurement accuracy without proportionally increasing device complexity, as the same polarization control mechanism addresses multiple signal quality issues
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 enhances the signal level and accuracy of range and velocity measurements by optimizing the polarization control of light in LIDAR systems, leading to improved performance in autonomous vehicle navigation and environmental sensing.
Implementation Method 1
The first arm includes a first phase shifter and a second phase shifter that are configured to be controlled to set a phase of the first arm relative to the second arm
Implementation Method 2
The dual-polarization grating coupler is configured to couple the light from the first port into a first beam having a first polarization orientation. The dual-polarization grating coupler is configured to couple the light from the second arm into a second beam with a second polarization orientation
Implementation Method 3
The grating coupler includes a first port to receive light from the first arm and a second port configured to receive light from the second arm
Data Source
AI summary
A light detection and ranging (LIDAR) pixel includes a splitter, a grating coupler, and a phase shifter. The grating coupler is configured to emit a transmit beam that is based on a combination of a first portion of light and a second portion of light received from a laser. One or more first interconnects and one or more second interconnects couple the splitter to the grating coupler. The phase shifter is coupled to the one or more first interconnects and configured to vary a phase of the first portion of the light relative to a phase of the second portion of the light.