Pound-Drever-Hall laser frequency stabilizing system without phase shifter

Abstract

A Pound-Drever-Hall laser frequency stabilizing system without a phase shifter comprises a laser source, an MCU controller, a DDS radio frequency signal source, an electrooptical modulator, a reference cavity, a photoelectric detector, a frequency selecting amplification network, a mixer, a low pass filter, an A / D converter, a D / A converter, a DSP, a switch module and a PZT driving circuit. The Pound-Drever-Hall laser frequency stabilizing system has two operating modes, the DSP is used for selecting the operating modes, and the switch module is used for switching one sort of radio frequency reference signals output by the DDS radio frequency signal source or frequency drift signals output by the conditioned photoelectric detector to enter the mixer. The DDS radio frequency signal source generates two ways of orthogonal radio frequency reference signals which conduct mixing with signals selected by the switch module respectively, phase sensitive detection and control strategy calculation is carried out in the DSP after collection, and thus the effect of frequency stabilization can be achieved. By means of the Pound-Drever-Hall laser frequency stabilizing system without the phase shifter, frequency stabilizing accuracy is improved, and full-automatic laser tracking locking is achieved.

Description

technical field [0001] The invention belongs to the technical field of laser frequency stabilization systems, and relates to a Pound-Drever-Hall laser frequency stabilization system without a phase shifter. Background technique [0002] The Pound-Drever-Hall frequency stabilization method is widely used in narrow linewidth laser frequency stabilization systems due to its strong anti-interference ability, not easy to lose lock, high stability, and not limited by wavelength. The principle of this method is: the output beam of the laser is phase-modulated by the electro-optic modulator, and then it is vertically incident on the F-P reference cavity, and the reflected light is beat on the photodetector. If the laser frequency is equal to the resonance frequency of the reference cavity, the beat frequency output is zero; otherwise, there is a beat frequency current output. After a certain phase shift, the RF reference signal is mixed and demodulated with the beat frequency signa...

AI Technical Summary

Problems solved by technology

This method is based on human eye observation and manual adjustment, so the error is large; the digital phase shifter needs to add a phase detection and phase shift control unit to the system, which increases the complexity of the system. At the same time, the added unit itself inevitably introduces Phase error reduces the frequency stabilization accuracy of the system

Images