OPTICAL-FIBER VIBRATION SENSOR USING STEP INTERFEROMETRY

An all-fiber vibration sensor based on step interferometry is describe d. The sensor consists of a modified Michelson interferometer in which the ends of the reference and signal arms are assembled and fixed tog ether to produce regular distributed interference fringes. Five photod etectors with relative phase shifts of pi/2 placed on the fringes acqu ire five intensity patterns simultaneously. One reconstructs the vibra tion amplitude by using the well-known five-step algorithm. A vibratio n sensor with these characteristics was constructed, and its performan ce was investigated. (C) 1996 Optical Society of America