基于微波频差转换的光学拍频研究

光学拍频是大学物理和光学实验教学中的重要内容.由于激光器存在中心波长漂移问题,实验中不易产生可观测的拍频信号.受到微波光子技术中微波波段和光波波段相互作用机理的启发,提出了基于微波频差转换的光学拍频方法.借助强度调制和相位调制将两个频差较小的微波信号调制到同一光载波上,结合光学滤波器获得了两个频差极小的稳定光信号,利用光电探测器实现光学拍频,从仿真和实验两个层面分别获得了可视化的低频拍频信号.该研究为大学物理和光学实验提供了与科学前沿相结合的实验方案,可拓展教学内容和教学深度,有利于培养学生的科学素养.

Optical beat based on microwave frequency difference conversion

Optical beat frequency is an important teaching content in college physics and optical experiment.Due to the central wavelength drift of the laser,it is difficult to produce observable beat signal in the experiment.Inspired by the transformation between electric domain and optical domain in microwave photonic technology,an optical beat frequency method based on microwave frequency difference conversion is proposed.By means of intensity modulation and phase modulation,two microwave signals with small frequency difference are modulated to the same optical carrier.Two stable optical signals with minimum frequency difference are obtained by combining with optical filter.Optical beat is realized by using photoelectric detector.Visual low-frequency beat signal is obtained by the simulation and experiment.This method provides an experimental scheme for college physics and optical experiments combined with the cutting-edge of science.It can expand the teaching content and depth,and can also help to cultivate students’scientific literacy.