p $\varepsilon$ -Resolution Fiber Grating Sensor With Adjustable Measurement Range and Ultralow Probe Power

A novel active fiber grating sensor system based on injection-locking and Pound-Drever-Hall techniques is presented. In demonstrational experiments, pε-level strain resolution is achieved with a very low probe power down to -70 dBm, which is at least 50 dB lower compared with the classical Pound-Drever-Hall technique. Besides, the measurement range of the sensor can be adjusted over a large scale up to 17 dB by changing the injection ratio. With the ultrahigh resolution, ultralow probe power, and adjustable measurement range, the proposed sensor has great potential in high-resolution and large-scale sensor networks.