Multi-wavelength Fiber Laser Source for LiDAR Scanning Speed
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Solution Overview
Problem
Current laser radar systems using single-beam narrow-band lasers have limited detection range and speed, necessitating the development of a more efficient multi-wavelength source for expanded detection capabilities.
Innovation Solution
A multi-wavelength narrow-linewidth single-frequency optical fiber laser source is achieved through a self-injection locking structure combined with a short linear resonant cavity and an optical filter module, utilizing high- and low-reflectivity chirped optical fiber gratings, a high gain optical fiber, and semiconductor components for enhanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-beam narrow-band laser is used as an emitter, then the system structure is simple, but the detection range is limited and the scanning speed is low
Solution Approach 1:
The patent divides the laser source into multiple independent wavelength channels (e.g., 1530nm, 1550nm, 1570nm) that operate simultaneously. Each wavelength corresponds to a separate beam path, allowing parallel detection across multiple ground spots. This segmentation enables the system to achieve both structural simplicity (using standardized components at each wavelength) and high scanning speed (through multi-point simultaneous measurement).
Solution Approach 2:
The patent employs universal optical components that can handle multiple wavelengths, such as dichroic mirrors that reflect specific wavelength bands while transmitting others, and beam combiners that merge multiple wavelength beams into a single optical path. This multi-functionality allows the system to maintain relatively simple structure while achieving multi-wavelength operation and high-speed scanning capabilities.
2Ease of operation
If a single-beam narrow-band laser is used, then the system is easy to operate, but the detection range is small
Solution Approach 1:
The detection space is segmented into multiple wavelength-specific channels, each covering a distinct ground area. By operating multiple wavelengths simultaneously, the system expands the total detection area without requiring complex mechanical scanning. Each wavelength channel can be independently optimized and operated, maintaining ease of operation while collectively covering a larger area.
Solution Approach 2:
The patent transitions from single-point detection in one dimension to multi-point detection across multiple wavelength dimensions. By adding the wavelength dimension as an additional degree of freedom, the system expands detection coverage without increasing mechanical complexity, thus maintaining ease of operation while greatly expanding detection range.
3Area of stationary object
If a multi-beam narrow-band laser is used to expand detection range, then the detection range increases, but the system complexity increases
Solution Approach 1:
The patent merges multiple wavelength beams into a single optical path using beam combiners and dichroic mirrors. This merging approach allows the system to achieve multi-beam functionality (expanded detection range) while maintaining a compact structure. The combined beam path reduces the number of separate optical trains and simplifies the overall system architecture compared to fully independent multi-beam systems.
Solution Approach 2:
The patent uses universal optical components that serve multiple wavelength channels simultaneously. For example, a single beam combiner handles multiple wavelengths, and a single receiver system processes signals from all wavelengths. This multi-functionality reduces the total component count and system complexity while maintaining expanded detection range through multi-wavelength operation.
4Ease of manufacture
If conventional laser sources are used, then the system is simple to implement, but the laser linewidth is broad and detection precision is limited
Solution Approach 1:
The patent changes the key parameter of laser linewidth by using externally cavity-diode lasers (ECDLs) instead of conventional laser sources. ECDLs provide narrow linewidths (e.g., <100 kHz) compared to standard diode lasers, significantly improving detection precision for applications like velocity measurement and ranging. The system maintains ease of implementation by using commercially available ECDL modules that can be integrated into standard laser radar architectures.
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 configuration enables the generation of a high-gain, multi-wavelength single-frequency laser with improved detection range and speed, achieving noise suppression and optimized optical performance for laser radar systems.
Implementation Method 1
the low-reflectivity chirped optical fiber grating and the high-reflectivity chirped optical fiber grating form front and back cavity mirrors of the laser resonant cavity to realize laser oscillation in the cavity
Implementation Method 2
the high gain optical fiber is used as a gain medium of a laser resonant cavity with a compact structure
Implementation Method 3
After selecting a plurality of wavelengths corresponding to central frequencies via the optical filter module with a certain free spectrum width
Implementation Method 4
the laser is injected back into the laser resonant cavity via the optical circulator and the optical coupler, combined with a short linear resonant cavity structure, the resonant cavity after self-injection locking lases a single-frequency optical fiber laser
Data Source
AI summary
A multi-wavelength single-frequency optical fiber laser source for a laser radar system includes a resonant cavity composed of a high-reflectivity chirped optical fiber grating, a high gain optical fiber and a low-reflectivity chirped optical fiber grating, a single-mode semiconductor pump laser served as a pump light source, an optical wavelength division multiplexer, an optical coupler, an optical isolator, an optical circulator, an optical filter module, and a semiconductor optical amplifier. The pump light source performs optical fiber core pumping with respect to the high gain optical fiber. A portion of the wide-spectrum laser is filtered by the optical filter module to obtain a wavelength corresponding to a specific central frequency. Multi-wavelength laser lasing with a narrow linewidth and single longitudinal mode is implemented by combining a short linear resonant cavity structure and the optical filter module.