一种提高迈克尔逊干涉系统抗干扰能力的新方法

A New Method of Anti-Jamming Ability Improvement for Michelson Interferometer

为了提高迈克尔逊干涉系统的抗干扰能力,取代传统的动镜扫描结构,设计了基于电光调制晶体折射率实现光程扫描的干涉系统。通过加载在可变折射率晶体上的调制电信号,使晶体折射率产生周期性变化,从而在原有系统光路中调制折射率改变光程差。通过理论计算获得了电光调制过程中系统可以产生的最大光程差,并仿真分析了晶体厚度及晶体衍射效率对调制过程的影响。经仿真分析可知,随着调制电压范围的增大,可获得的光程变化范围也增大,从而系统光谱分辨能力也相应增大。同时,在调制过程中设置调制范围使衍射损失的能量小于总能量的10%,从而保证较好信噪比。实验结果显示,随着调制电压的变化,干涉条纹产生周期性移动,但超过一定范围时会产生非线性误差。通过修正算法后系统光谱分辨率可达7.2cm-1。在无抗震实验平台的条件下,传统干涉系统的相对误差超过20%,而本系统的相对误差低于3%,证明了系统采用静态电光调制后抗干扰能力显著增强。

In order to improve anti-jamming capability of Michelson interferometer system ,replace the traditional structure of the moving mirror scanning was replaced ,an interference system based on electro-optic modulation of crystal refractive index was de-signed to achieve optical path scanning .The system modulated voltage signal on the variable refractive crystal ,to generate cycli-cal changes ,changed the refractive index to control optical path difference in the original optical path system .Using electronic scanning to replace of mechanical scanning ,improved the system’s noise immunity was improved .In the electro-optic modulation process ,computed the maximum optical path difference of the system was computed ,and analyzed of the crystal thickness and crystal diffraction efficiency of the modulation process were analyzed .The simulation experiment shows that ,with the modula-tion voltage range increasing ,the available range of the optical path is also increased ,and the system spectrum resolving power will also increase accordingly .Meanwhile ,in the modulation process set the modulation range was set to make the energy of dif-fraction energy losses less than 10% of the total energy ,so as to ensure a better signal to noise ratio .Experimental results show that ,as the modulation voltage changes ,interference fringes occurred continuously moved .When the voltage is further in-creased ,the nonlinear error appears .After non-linear error correction for the system ,spectrum resolution reached to 7.2 cm -1 , slightly lower than the original system .But its anti-jamming capability is greatly enhanced ,as in the absence of experimental platform for seismic conditions ,conventional interferometer relative error is more than 20% ,while the relative error of the sys-tem is less than 5% ,in line with the design requirements .It was proved that the anti-jamming capability of the system was en-hanced greatly ,when the static electro-optical modulation was used .