Tunable Light Source Frequency Locking Under Wideband Modulation
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Solution Overview
Problem
Current frequency stabilization methods for tunable light sources in micro-probe laser interferometers face challenges in achieving center frequency stability during large-range and high-bandwidth wavelength tuning, leading to inaccurate measurements due to small tuning frequency and range limitations.
Innovation Solution
A frequency stabilization method and system based on characteristic curve reconstruction, which involves outputting laser beams into an acetylene absorption chamber, converting signals, and using a combination of peak detection, phase compensation, and proportional integral control to adjust the driving current and temperature of the laser, thereby stabilizing the output frequency at a target locking point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If passive frequency stabilization technology is used to improve wavelength output stability, then center frequency stability is improved, but tuning range and bandwidth are limited
Solution Approach 1:
The patent implements active frequency stabilization by introducing a feedback control system that continuously monitors the laser wavelength using an acetylene absorption chamber and adjusts the laser current in real-time to maintain wavelength stability, enabling both large-range tuning and high stability
Solution Approach 2:
The patent dynamically adjusts the laser driving current parameter to achieve wavelength tuning across a broad range while using feedback control to maintain stability, thereby resolving the contradiction between tuning range and frequency stability
2Reliability
If active frequency stabilization technology with external reference benchmarks is used, then center frequency stability is improved, but measurement speed and dynamic performance deteriorate
Solution Approach 1:
The patent employs periodic wavelength modulation at high frequencies (up to several MHz) combined with lock-in detection techniques, enabling rapid frequency stabilization that maintains both measurement speed and stability through oscillatory measurement cycles
Solution Approach 2:
The patent replaces traditional mechanical wavelength tuning mechanisms with direct electrical current modulation of the laser diode, enabling high-speed wavelength scanning and stabilization without mechanical inertia limitations
3Reliability
If small-range and low-speed wavelength modulation is used, then frequency stabilization is achieved, but dynamic measurement performance and maximum measurement speed deteriorate
Solution Approach 1:
The patent implements dynamic wavelength modulation where the laser wavelength is continuously swept at high speeds through controlled current variation, combined with real-time feedback stabilization that adapts to the dynamic tuning conditions, achieving both high speed and frequency stability
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 high-precision frequency stabilization under large-amplitude and high-bandwidth modulation, allowing for accurate control of the center frequency during large-range and high-bandwidth tuning, enhancing the measurement accuracy of micro-probe laser interferometers.
Implementation Method 1
a frequency stabilization method and system for tunable light sources based on characteristic curve reconstruction... outputting, by a laser (i.e., a tunable light source), laser to a fiber optic coupler... output light of the distributed feedback laser 2 is transmitted to a fiber optic isolator 3 through fiber optics, and then a fiber optic coupler 4 divides the output light into emergent light and signal light. The photodetector 6 converts the signal light passing through an acetylene absorption chamber 5 to an electrical signal
Data Source
AI summary
A frequency stabilization method and system for tunable light sources based on characteristic curve reconstruction are provided, which relate the field of frequency stabilization technologies of modulation absorption spectrum. A set of frequency stabilization control method and system based on internal modulation absorption spectroscopy of light source is constructed, and a high-precision laser frequency stabilization method under large-amplitude and high-bandwidth frequency modulation based on frequency discrimination curve reconstruction is proposed to solve a problem that it is difficult for micro-probe laser interferometry measurement benchmark to balance large-amplitude and high-bandwidth frequency modulation, and high-precision frequency stabilization, resulting in that it is difficult to obtain high relative accuracy measurement under large-range measurement. Under the large-amplitude and high-bandwidth frequency modulation, a distortion model of the frequency discrimination curve and a distortion correction model are constructed, which is used for feedback adjustment of phase compensation and reconstructing the frequency discrimination curve.