具有实时监测能力的光纤光栅传感系统时域地址查询技术

时钟信号控制下的脉冲宽带光源发出的光波,进入4个光栅组成的间距为10m的光栅串。利用受同一时钟信号控制的1×4模拟电子开关,将各传感元的反射光脉冲依次分配至相应的输出信道,实现时域地址查询,并对各传感元位置的待测应变进行实时监测。引入非平衡迈克耳孙干涉解调装置,将来自传感光栅的受待测应变诱导而至的波长漂移信息变为相移信息,定标后便可实现传感信号的解调。1556nm波长时,系统传感灵敏度的实验值为1.658°/με,与理论值1.673°/με基本吻合。

Time-Domain Addressing Technique for Fiber Bragg Grating Sensor System with the Function of Real-Time Monitoring

The emission of light wave from a pulsed broadband source controlled by a clock is injected into a four-element fiber Bragg grating sensor array. A technique of time-domain addressing is introduced to interrogate the gratings spaced 10 m apart by employing a 1×4 analog electrical switches, which is controlled by the same clock. The switches allocate the pulses reflected by the sensor elements into corresponding output channels to make the system performing the function of real-time monitoring the measurand. Demodulated with an unbalanced Michelson interferometer, which converts the wavelength shifts to phase changes, the system is demonstrated to be with a sensing sensitivity of 1.658°/με at the wavelength of 1556 nm. It matches the theoretical value of 1.673°/με basically.