Large vibration response bandwidth and high spatial resolution FDM φ-OTDR system based on Optical Pulse Compression and Compressive Sensing

• DOI: 10.1364/opticaopen.28862393
• Publication Date: 2025-04-25T10:07:40Z
• Authors: Xingliang Shen; Hong Dang; Jialong Li; Yihong Xiao; Aoyan Zhang; Hua Zheng; Huanhuan Liu; Liyang Shao; Chao Lu; Perry Shum
• Keywords: Pulse compression; Optical time-domain reflectometer

Heterodyne coherent distributed acoustic sensing (DAS) system has witnessed substantial expansion in applications due to its specific advantages like long distance, real-time response and high accuracy. However, the trade-off between vibration bandwidth distance limits broader deployment. The frequency-division-multiplexing (FDM) technique is a well-known solution. But, avoid inter-channel crosstalk, it requires wide (like photodetector modulator) or compromises spatial resolution by enhancing pulse duration, which increases cost degrading performance, respectively. In this work, we propose combine optical compression (OPC) compressive (CS) traditional FDM φ-OTDR. Experimental results demonstrate detection of 30 kHz signal over 5.2 km fiber identification two regions spaced 8 m apart, achieving beyond duration limit. This proposed method breaks trade-offs bandwidth, conventional φ-OTDR without upgrading hardware broadens application DAS monitoring.