A precision edge filter interrogation system for mine Fiber Bragg Grating micro-seismic sensors

The edge filter approach using a distributed feedback laser diode is well suited for interrogating Fiber Bragg Grating micro-seismic sensors. This paper presents the design and implementation of a novel precision edge filter interrogation system based on digital signal processing technology. The experimental study of the temperature tuning characteristics, system composition, and operating principle are introduced in detail. The results show that the system achieves a bandwidth range from 0.5 Hz to 450 Hz. The working-point control accuracy reaches up to 0.1 %, while the time synchronization precision is about 0.6 us. It is expected to be applied in distributed fiber optic micro-seismic system for underground coal mines.