Coherent LIDAR Photonic Integrated Circuit Speckle Mitigation
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Solution Overview
Problem
Coherent LIDAR systems face challenges in achieving long-range detection (>200 m), high data rate (>1M pixels/s), and high optical resolution (>100 vertical pixels) due to time-of-flight limitations and speckle effects from fluctuating targets.
Innovation Solution
The implementation of a photonic integrated circuit (PIC) with a hybrid photonic integrated circuit system, which includes separate transmitting and receiving structures, and the use of spatially parallel optical channels to generate local oscillator signals, mitigates the impact of speckle and time-of-flight limitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple measurements are integrated to mitigate speckle, then detection reliability is improved, but data rate deteriorates
Solution Approach 1:
The patent segments the optical detection into multiple independent vertical channels (resolving elements) that operate in parallel. Each channel performs independent coherent detection and integration, allowing simultaneous accumulation of measurements across multiple channels. This segmentation enables the system to maintain high data rate while achieving speckle mitigation through spatial diversity across the segmented channels.
2Measurement precision
If the number of vertical channels is increased to improve optical resolution, then measurement precision is improved, but device complexity deteriorates
Solution Approach 1:
The patent implements a universal optical architecture where a single photonic integrated circuit core performs multiple functions: it generates the optical signal, performs coherent detection across multiple vertical channels, and integrates measurements. This multi-functional design allows high optical resolution through multiple vertical channels while avoiding the complexity of separate dedicated systems for each function.
Solution Approach 2:
The patent merges the local oscillator generation, signal detection, and measurement integration functions into a unified coherent detection system. By combining these functions within a single photonic integrated circuit, the system achieves high optical resolution through multiple vertical channels without the complexity of separate distributed systems.
3Reliability
If coherent detection is used to achieve immunity to optical interference, then reliability is improved, but time-of-flight limitations worsen data rate
Solution Approach 1:
The patent employs continuous wave (CW) coherent detection where the laser operates continuously rather than in pulsed mode. This continuous operation allows for continuous measurement and integration across multiple vertical channels, overcoming the time-of-flight limitations that would restrict data rate in pulsed systems while maintaining the interference immunity benefits of coherent detection.
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 a coherent LIDAR system to achieve high optical resolution, high data rate, and long-range detection capabilities while reducing optical losses and power consumption, making it suitable for autonomous vehicle applications.
Implementation Method 1
at least a first electromagnetic radiation emitting structure formed by a photonic integrated circuit configured to generate a coherent first electromagnetic radiation
Implementation Method 2
a plurality of optical components configured to guide electromagnetic radiation from the at least first and second electromagnetic radiation emitting structures to an outside of the optical system and from the outside of the optical system to the at least first and second electromagnetic radiation detecting structures
Implementation Method 3
a plurality of optical components configured to guide electromagnetic radiation
Implementation Method 4
at least a first electromagnetic radiation detecting structure configured to detect the first and second coherent electromagnetic radiation
Implementation Method 5
ability to detect both the range and range-rate (relative velocity of a target) to a target
Implementation Method 6
time-of-flight (TOF) limitations on the detection process
Data Source
AI summary
A light detection and ranging system is provided using a first electromagnetic radiation of a first emitting structure as local oscillator signal for a second electromagnetic radiation received from the outside of the light detection and ranging system, wherein the first and second electromagnetic radiations are coherent and the resulting signal is detected by a detecting structure. The resulting signal corresponds to an information of a target at the outside of the light detection and ranging system.