High-Spatial-Resolution and High-Speed Distributed Vibration Sensing Based on $\varphi-\text{OFDR}$

We report on a high-spatial-resolution and high-speed phase sensitive optical frequency domain reflectometry system for dynamic measurement based on a distributed feedback laser utilizing the feedback iteration algorithm for linear frequency modulation, which greatly simplifies the experimental equipment and reduces the cost. Fiber with embedded weak reflector array spaced at 4cm intervals has been adopted as the sensing fiber, and a single-branch experimental structure is employed. Demonstration in terms of distributed vibration sensing with a 4cm spatial resolution and 4kHz repetition frequency has been verified, showing excellent crosstalk suppression capability and a high SNR of 50dB.