Coherent Pulsed Lidar System With Semiconductor Optical Amplifier
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Solution Overview
Problem
Current lidar systems face challenges in efficiently determining the distance to targets with varying reflectivity and in achieving high-resolution scanning patterns, particularly in environments with complex geometries and dynamic targets.
Innovation Solution
The development of a lidar system that incorporates a light source with a semiconductor optical amplifier (SOA) and a local-oscillator (LO) laser, combined with a coherent pulsed operation and advanced scanning mechanisms, allows for precise distance measurement and high-resolution scanning by coherently mixing LO light with received pulses to enhance signal processing and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional lidar systems use standard light sources and receivers, then the system structure is simple, but the accuracy and resolution of distance measurements are insufficient
Solution Approach 1:
The patent combines a semiconductor optical amplifier (SOA) with a local oscillator (LO) laser in a single coherent pulsed lidar system. The SOA amplifies the LO laser light to create coherent pulses that are mixed with returned light signals, enabling enhanced measurement precision through coherent detection while maintaining a relatively compact integrated structure.
Solution Approach 2:
The system changes the operating parameters by using coherent pulsed operation with specific pulse widths (e.g., 100 ps to 1 ns) and repetition rates. The coherent mixing of LO light with returned pulses enables detection of weak signals with high precision, improving distance measurement accuracy through parameter optimization rather than simply increasing system complexity.
2Measurement precision
If conventional lidar systems use basic scanning mechanisms, then the device complexity is low, but the resolution of scanning patterns is insufficient for complex geometries
Solution Approach 1:
The patent employs dynamic scanning mechanisms that can adaptively adjust scan patterns based on the complexity of the target geometry. The system uses programmable scanners that can modify scanning speeds, angles, and patterns in real-time to achieve high resolution for complex surfaces while maintaining lower complexity for simple targets, optimizing the balance between resolution and device complexity.
3Adaptability or versatility
If conventional lidar systems do not account for varying reflectivity, then the system is simpler to operate, but the ability to detect and map targets in complex environments is reduced
Solution Approach 1:
The coherent pulsed lidar system incorporates feedback mechanisms that continuously monitor the strength and characteristics of returned light pulses. By analyzing the amplitude and phase information from the coherent mixing of LO and returned light, the system automatically adapts to varying target reflectivity and environmental conditions, enhancing detection capability while maintaining ease of operation through automated adjustment.
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 significantly improves the accuracy and resolution of distance measurements and scanning patterns, enabling better detection and mapping of targets in complex environments with varying reflectivity.
Implementation Method 1
a light source with a semiconductor optical amplifier (SOA) and a local-oscillator (LO) laser, combined with a coherent pulsed operation
Implementation Method 2
coherently mixing LO light with received pulses to enhance signal processing and accuracy
Implementation Method 3
The light source emits light toward a target which scatters the light, and some of the scattered light is received back at the receiver
Implementation Method 4
the lidar system may determine the distance to the target based on the time of flight for a pulse of light emitted by the light source to travel to the target and back to the lidar system
Implementation Method 5
The light source emits light toward a target which scatters the light, and some of the scattered light is received back at the receiver
Data Source
AI summary
In one embodiment, a lidar system includes a light source configured to emit local-oscillator (LO) light and pulses of light, the emitted pulses of light including a first emitted pulse of light, where an optical frequency of the first emitted pulse of light is offset from an optical frequency of the LO light by a first frequency offset. The lidar system further includes a receiver configured to detect the LO light and a first received pulse of light, the first received pulse of light including light from the first emitted pulse of light scattered by a target located a distance from the lidar system. The receiver includes a detector, where: the LO light and the first received pulse of light are coherently mixed together at the detector, and the detector is configured to produce a photocurrent signal corresponding to the coherent mixing.