Experimental Investigation of Coupling Fiber-Optic Vibration Sensor

A new kind of coupling fiber-optic vibration sensor whose sensing mechanism based on the characteristic of the coupler´s coupling output ratio sensitive to the length variation of coupling zone is presented and demonstrated in this paper. The working principle of coupling fiber-optic vibration sensor is analyzed and a prototype system including a sensor head, a low cost control unit and a software package has been successful developed. The static and dynamic test of the coupling fiber-optic vibration sensor was done and the response curve when applied with vibration and shock is shown. The techniques of both measurement and compensation are addressed. The behaviors of the coupling fiber-optic vibration sensor are closely agreed with the response of a high precision piezoelectric accelerometer. Experimental results show that the coupling fiber-optic vibration sensor not only meets the requirement of vibration measurement, but also has the merits of high sensitivity, light weight, low cost etc.