Ultra-long-distance (> 160 km) distributed optic fiber vibration sensing system without an in-line repeater

摘要

We proposed a distributed optic fiber vibration sensing system that can realize a sensing distance of more than 160 km without a repeater. The system's optical structure is based on the Mach-Zehnder and Sagnac hybrid interference technique. To increase the monitoring distance, we used a reflective erbium-doped fiber amplifier (EDFA) instead of a traditional reflector at the end of the sensing system. In addition, a phase-generated carrier was applied to eliminate the parasitic interferometric effects of Rayleigh scattering. (C) 2019 Optical Society of America