Mach-Zehnder and modified Sagnac-distributed fiber-optic impact sensor

摘要

An interferometric technique is described to detect and locate perturbations along an optical fiber. This distributed sensor has a position-dependent response to time-varying disturbances such as strain or temperature. A modified Sagnac interferometer configuration that incorporates an additional coupler and a mirror allows separation of the Sagnac and the Mach-Zehnder signals. Operation of the new configuration was verified experimentally with a 100-m-long sensing fiber. The discrepancy between actual and measured locations of disturbances applied to the fiber did not exceed 0.6 m. #1998 Optical Society of America OCIS codes: 060.2370, 120.3180, 130.6010, 120.0280.