高稳定大量程复合光纤干涉位移测量系统研究

为了使位移测量系统达到大量程、高分辨率,采用复合光纤干涉的方法,进行了理论分析和实验验证。利用光纤光栅作为反射镜,构成两个干涉光路几乎共路的光纤迈克尔逊干涉仪。其中一个光纤迈克尔逊干涉仪通过反馈控制补偿环境干扰对测量系统的影响,使测量系统适合在线测量;另一个干涉仪用于完成测量工作。两个不同波长的光同时作用于完成测量的干涉仪中,测量量程由两个波长的合成波干涉信号确定,使测量量程大于1mm;测量分辨率由其中一个单波长干涉信号确定,测量分辨率小于1nm。结果表明,这种基于复合光纤干涉仪的位移测量系统可以实现大量程、高稳定的位移在线测量。

High-stability and large-displacement measurement system based on multiplexed fiber interferometry

In order to make the displacement measuring system achieve the large-range and high-resolution, theoretical analysis and experimental verification were conducted with the multiplexed fiber interferometer. Two fiber Michelson interferometers sharing common-interferometric-optical path were configured by employing fiber Bragg gratings as in-fiber reflective mirrors. One of the interferometer was used to stabilize the measurement system with a feedback loop compensating the influence induced by the environmental disturbance so that the measurement system was kept stable enough for on-line measurement, while the other one was for performing the measurement task. Two different wavelengths are working simultaneously in the measurement interferometer. The measurement range determined by the synthetic-wavelength interferometric signal of the two wavelengths was expanded to be larger than 1mm, while the measurement resolution determined by one of the single-wavelength interferometric signals was maintained less than 1nm. The displacement measurement system achieved the large-range and high-resolution purpose based on multiplexed fiber interferometry.