公开(公告)号：US11860008B2

公开(公告)日：2024-01-02

申请号：US17920809

申请日：2022-05-06

Applicant: NANJING UNIVERSITY

Inventor： Yixin Zhang ,  Jinyu Song ,  Xuping Zhang ,  Zhewen Ding ,  Shuai Tong ,  Shun Wang ,  Feng Wang

IPC: G01D5/353

CPC classification number: G01D5/35358

Abstract: A self-heterodyne phase-sensitive optical time domain reflectometry (φ-OTDR) system with a free multi-spatial resolution includes a narrow linewidth laser source, a 1×3 fiber-optic coupler, three acousto-optic modulators (AGMs), a 3×1 fiber-optic coupler, two time-delay fibers, an erbium-doped fiber amplifier (EDFA), a circulator, a photodetector, an electrical amplifier, three filters, a data acquisition card, a pulse signal generator, and a driver module. A plurality of acousto-optic modulators using the same driver are used to couple probe light with different pulse intervals and different frequency shifts and then inject the probe light into a fiber, such that a self-heterodyne detection structure with a multi-spatial resolution is implemented, which suppressed optical background noise such as coherent fading noise, phase noise introduced by a frequency drift of a light source, and pseudo-random noise (PRN).