弹光晶体频率温度系数对弹光调制系统的影响

分析了（xyt）φ1切型长度伸缩振动模式下硒化锌晶体谐振器的频率温度特性。推导了温度与硒化锌晶体的密度、杨氏模量和膨胀等材料性质的关系,计算了硒化锌晶体的频率温度系数。结果表明,相对于硒化锌的一级频率温度系数而言,硒化锌的高级频率温度系数可以忽略。弹光调制系统工作时所产生的热量会引起温度变化,从而导致谐振频率改变。当弹光调制系统工作在50kHz的谐振频率位置时,硒化锌晶体温度每改变1℃,晶体本征频率改变2.5Hz,相对于弹光调制系统16Hz的谐振半峰宽而言,该频率温度漂移不可忽略。

Influences of Frequency-temperature Coefficient of Elastic-optic Crystal on Elastic-optic Modulation System

The frequency-temperature characteristics of zinc selenide(ZnSe) resonator were investigated under the condition of(xyt)φ1-cut of the length of stretching modes.The relationship of temperature with the properties of ZnSe crystal such as density,Young’s modulus and expansion was deduced and its frequency-temperature coefficient was calculated.The results show that the ZnSe higher order frequency-temperature coefficient can be negligible with respect to its first order frequency-temperature coefficient.The temperature changes with the heat caused by elastic-optic modulation system,thus the resonant frequency changes.One degree change of the temperature of ZnSe crystal induces 2.5 Hz changes of eigen frequency when the resonant frequency of elastic-optic modulation system is set to be 50 kHz,and the shift of frequency-temperature can not be ignored relative to the 16 Hz resonant half peak width.