Wavelength Division Multiplexed LiDAR for Wide Field of View
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Solution Overview
Problem
Current LiDAR systems face limitations in achieving a wide field of view without using lasers with large tuning ranges, and traditional 2D phased arrays suffer from packing constraints and aliasing effects, which reduce the field of view and introduce losses and false detections.
Innovation Solution
The implementation of wavelength division multiplexed LiDAR systems using a multiwavelength beam from multiple individual lasers, where individual wavelengths are separated into scan lines, allowing for 2D scanning with directional control and selective reception of reflected light, employing active optical phased arrays and optical splitters, and integrating these components onto a single substrate using CMOS techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional 2D phased arrays are used to achieve wide field of view, then the field of view can be expanded, but packing constraints and aliasing effects occur which reduce the field of view and introduce losses and false detections
Solution Approach 1:
The patent segments the 2D scanning function into two independent 1D scanning dimensions. The first dimension uses a 1D phased array for fast scanning, while the second dimension uses a rotating mirror for slow scanning. This segmentation avoids the packing constraints and aliasing effects of 2D phased arrays while maintaining a wide field of view and reducing false detections.
Solution Approach 2:
The patent introduces a temporal dimension by using sequential scanning: the 1D phased array scans rapidly in one dimension while the rotating mirror progressively scans in the perpendicular dimension over time. This dimensional transformation converts a spatial 2D array problem into a combination of 1D spatial array and temporal scanning, eliminating aliasing effects.
2Adaptability or versatility
If lasers with large tuning ranges are used to achieve wide field of view, then the field of view can be expanded, but the system complexity and cost increase
Solution Approach 1:
The patent uses multiple fixed-wavelength lasers instead of a single laser with large tuning range. Each laser operates at a specific wavelength and contributes to a specific scan line. This segmentation of the wavelength domain allows wide field of view achievement through spatial scanning rather than requiring large wavelength tuning ranges, thereby reducing laser complexity.
Solution Approach 2:
Multiple fixed-wavelength lasers work together to provide the functionality that would otherwise require a single tunable laser. Each laser is simpler and more reliable, but collectively they achieve the same wide field of view coverage through wavelength division multiplexing and sequential scanning.
3Adaptability or versatility
If 1D phased arrays with multiple scan lines are used, then the field of view is improved, but continuous 2D scanning capability is reduced
Solution Approach 1:
The patent ensures continuous scanning by combining the rapid scanning of the 1D phased array with the continuous rotation of the mirror. While the phased array completes multiple fast scan lines, the mirror continuously rotates to progress through the second dimension, ensuring no gaps in the scanning coverage and maintaining continuous useful action across the entire 2D field of view.
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 efficient ranging, sensing, and imaging capabilities with a wide field of view, reducing the need for complex tunable lasers and minimizing side lobes and false detections, while allowing for compact and manufacturable systems with continuous scanning in two dimensions.
Implementation Method 1
The individual wavelengths comprising the multiwavelength beam are separated out into individual beams—these separate wavelength beams forming individual scan lines
Implementation Method 2
an active optical phased array including phase shifters and grating emitters
Implementation Method 3
the emitters may be arranged in a curved pattern at the focal plane of a lens thereby allowing the directional control of emitted light
Data Source
AI summary
Aspects of the present disclosure describe wavelength division multiplexed LiDAR systems, methods, and structures that advantageously provide a wide field of view without employing lasers having a large tuning range.