可判向光纤位移干涉仪在振动测量中的应用

Direction-judgable Fiber Displacement Interferometer for Vibration Measurement

提出了基于光学多普勒效应和外差方法设计的可判向光纤位移干涉仪,装置采用光通信行业中已经发展成熟的器件,主要有带尾纤的半导体激光器、1×2光纤耦合器、三端口环形器、光纤探头、3×3光纤耦合器、探测器以及示波器等构成。在原有结构的基础上,增加了光纤放大器和光纤滤波器,大大提高了信号光光强。结合李萨如图形给出了可判向光纤位移干涉仪的信号处理方法。利用该干涉仪测量了压电陶瓷的振动,实验表明能够测量的最小振动峰峰值为0.43μm,并根据实验分析了干涉仪测量微位移的一些制约因素。研究表明,制约干涉仪测量微位移能力的主要因素是3×3光纤耦合器的非理想性,如3×3光纤耦合器输出干涉信号的位相差不恒定。

The Direction-judgable Fiber Displacement Interferometer （DJFDI） was proposed on the basis of optical Doppler effect and heterodyne technique. The proposed interfermeter was assembled by using the components well developed in the telecommunication industry, which consisted of a fiber-pigtail semiconductor laser, a 1×2 fiber coupler, a three-port optical circulator, a fiber probe, a 3×3 fiber coupler, a detector, an oscilloscope, and so on. Based on above original configuration, EDFA was utilized in DJFDI to enhance the signal power. The signal processing method based on Lissajous figure was brought forward. The vibration of piezoelectric ceramic vibration was measured to study its measurement capability of micro-displacement and the influencing factors. The experimental results show that the dominant influencing factor is nonideality of 3×3 fiber coupler, such as instability of the output phase difference of the DJFDI＇s interference signals.