High-precision frequency and phase discrimination signal processing method and device in laser offset frequency locking

Abstract

The invention discloses a high-precision frequency and phase discrimination signal processing method and device in laser offset frequency locking. The method comprises the steps: enabling tunable laser and a femtosecond optical frequency comb to pass through a beat frequency signal detection unit to obtain a beat frequency signal, performing analog-digital sampling on the beat frequency signal andthen enabling the signal to enter an FPGA development board for frequency and phase discrimination processing; multiplying the beat frequency signal by a reference signal and carrying out low-pass filtering; acquiring a corresponding phase through a coordinate rotation arithmetic unit; performing scaling processing on a phase after phase unwrapping, outputting an error voltage signal to an analogPID controller through a digital-to-analog converter, enabling the analog PID controller to generate a control signal to the tunable laser for closed-loop control, locking the frequency of a beat frequency signal to a reference signal, and calculating the signal-to-noise ratio, the frequency and the amplitude of the beat frequency signal. The invention solves the problems of difficulty in improving the frequency and phase discrimination precision of the beat frequency signal and small capture range in the offset frequency locking technology of locking the laser to the optical frequency comb,and can be widely applied to the field of laser precision measurement.

Description

technical field [0001] The invention belongs to a signal processing method and device in the technical field of laser frequency stabilization, in particular to a signal processing method and device for high-precision frequency and phase detection in laser bias frequency locking. Background technique [0002] Laser interferometry technology has the advantages of fast response speed, high measurement accuracy, strong anti-interference ability, and direct traceability to the definition of meters. Therefore, it is widely used in high-precision displacement measurement, ultra-precision processing and manufacturing, and instrument testing and calibration. In laser interferometry, the stability and traceability of laser frequency are the key factors affecting the measurement accuracy. The key to laser frequency stabilization technology is to select a stable reference frequency standard. The traditional laser frequency stabilization technology mainly locks the laser frequency to a p...

AI Technical Summary

Problems solved by technology

[0005] In order to solve the problems existing in the background technology, the present invention discloses a high-precision frequency and phase detection signal processing method and device in laser offset frequency locking, which solves the difficulty in improving the accuracy of beat frequency signal phase detection in laser frequency locking to optical frequency comb technology and the problem of small capture range

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