Fully distributed hydroacoustic sensing based on ultra-highly sensitive and lightweight fiber-optic hydrophone cable

•Through using BEOF and polarization independent demodulation algorithm, the NEP reaches the level of DSS0, and the low frequency response can reach up to a few tenths of 1 Hz, which is significant for long distance target detection.•The multilayer structure of the lightweight FOH cable is analyzed and optimized, whose average acoustic sensitivity is −137.2 dB re:1 rad/(μPa·m) with a flat frequency response at the range of 5 Hz ∼ 2 kHz, and low frequency response reaches up to −125.3 dB re:1 rad/(μPa·m) at 1 Hz.•Based on the characteristics of high sensitivity and broadband response, the system can detect various targets, and different boats, underwater small ROV, and frogman has been tracked in the field test.