Design And Experimental Research Of Single Longitudinal Mode YAG Laser Frequency Discrimination System

Single longitudinal mode laser has good characteristics such as coherence and monochromaticity. Therefore, it is widely used in accuracte measurement, optical communication, optical frequency scale, high resolution spectroscopy. The laser frequency is affected by its surroundings, usualy being a fluctuating signal as a variable of time. Frequency stabilization technique is required in order to stabilize laser frequency. Frequency discrimination system is a part of freuency stabilization system. We can use it to discriminate laser frequency, and get the frequency discrimination curve which is used by servocontrol system to stabilize laser frequency as control signal. The quality of the frequecy discrimination system largely influences frequency stabilization. The greater the slope of the frequecy discrimination curve, the better the frequency stabilizing system works. So the frequecy discrimination system is very important to the frequecy stability of the laser.This dissertation introduces the methods of several frequency discrimination technology and these fundamentals and characteristic. Then,we choose the Fabray-Perot confocal interferometer as laser frequency discrimination system and design the parameters of F-P confocal interferometer. We calculate the curves of permeance ratio and intensity of F-P confocal interferometer, and the curves of the dispersion-like frequecy discrimination in different incident angle by the computer software. Find out the best incident angle of the laser. The influence of the temperature and F-P confocal interferometer length drifting to F-P confocal interferometer are analysised. By using F-P confocal interferometer, large tuning frequency range can be achived, and the slope of the requecy discrimination system can be set by changing the incident angle of the laser beam in order to satisfy the required standard.In the experiment aspect,a single longitudinal mode laser using twisted mode technology is set up and configurated. Its single longitudinal mode output is tested by a Fabry-Perot etalon. F-P confocal interferometer is also built and configurated. We make the experimental research to the laser beam penetrating F-P confocal interferometer .