LiDAR Wavelength Stabilization via Feedback Control
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Solution Overview
Problem
LiDAR systems face challenges in suppressing optical crosstalk and wavelength stabilization due to temperature variations and limited availability of stable lasers, which affects the precision of filter width and range, leading to increased costs and reduced performance.
Innovation Solution
A stabilized LiDAR system that includes a laser with a thermocouple element for precise temperature control, a means for evaluating wavelength deviation, and a regulation mechanism to set the laser's working temperature to a setpoint wavelength, directly controlling the thermocouple based on the deviation measurement to maintain monochromatic radiation within a specified wavelength range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a narrow band-pass filter is used to reduce background light, then the signal-to-noise ratio is improved, but the filter width must be precisely controlled which requires highly stable laser wavelength that limits laser selection and increases cost
Solution Approach 1:
The patent changes the control parameter from temperature to wavelength directly. By measuring the actual wavelength and using feedback control to adjust the laser current, the system maintains precise wavelength stability without requiring extremely tight temperature control, thereby expanding laser selection options while maintaining narrow filter performance
Solution Approach 2:
The patent implements a feedback control system that measures the actual laser wavelength and adjusts the laser current accordingly. This closed-loop control maintains wavelength stability within the narrow filter passband, enabling the use of narrower filters to reduce background noise while accommodating broader laser selections
2Reliability
If temperature regulation is used to stabilize laser wavelength, then wavelength stability is improved, but the precision is limited by the unknown relationship between measured temperature and actual emitter temperature
Solution Approach 1:
The patent replaces the thermal control mechanism with an electrical control mechanism. Instead of adjusting temperature to control wavelength, the system directly adjusts the laser current based on wavelength measurements, eliminating the indirect thermal control path and its associated measurement uncertainties
Solution Approach 2:
The patent introduces wavelength measurement as an intermediary between the control system and the laser output. By measuring the actual wavelength and using this information to adjust the laser current, the system achieves precise wavelength control without relying on temperature measurements as an intermediate step
3Adaptability or versatility
If broad filter is used to accommodate process variations and temperature drifts, then laser selection flexibility is improved, but background light noise increases reducing LiDAR range
Solution Approach 1:
The patent uses feedback control to maintain precise wavelength alignment with the narrow filter passband. By continuously measuring the laser wavelength and adjusting the current, the system keeps the laser centered in the narrow filter window, enabling the use of narrow filters to reduce background noise while accommodating laser variations through active control
Solution Approach 2:
The patent transitions from static temperature setting to dynamic current adjustment. The laser current is continuously adjusted based on real-time wavelength measurements, allowing the system to adapt to process variations and maintain precise wavelength alignment with the narrow filter, thereby reducing background noise while maintaining laser flexibility
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 short-term and long-term stabilization by directly controlling the laser's emission wavelength, reducing errors associated with temperature regulation and improving the LiDAR system's performance and range by minimizing background noise and extending the filter's passband width.
Implementation Method 1
a thermocouple element, configured to set the working temperature of the laser
Data Source
AI summary
A stabilized LiDAR system and a method for stabilization. The LiDAR system includes a laser, the laser being designed for emission of monochromatic LiDAR radiation within a wavelength working range; a thermocouple element configured to set the working temperature of the laser; a means for evaluation, designed to determine, from the radiation emitted by the laser, a measure for the deviation from an actual wavelength of the radiation to a setpoint wavelength within the wavelength working range of the laser; and a means for regulation, designed to control the thermocouple element on the basis of the measure of deviation determined by the means for evaluation, in such a way that the working temperature of the laser is set to a value, at which the emitted monochromatic LiDAR radiation corresponds to the setpoint radiation.