Experimental Investigation of Coupling Fiber-Optic Sensor for Vibration Measurement

According to the character of fiber-optic coupler, its coupling output is sensitive to the variation of coupling region's length. A new kind of coupling fiber-optic vibration sensor is presented base on this principle. The two ends of coupler are fixed onto a V-groove substrate and the coupling region is suspended in the air to realize the measurement of vibration. A prototype fiber optic vibration detection system has been successfully developed, including a sensor head, a low-cost control unit and a software package for signal processing with high resolution. The response of a simply supported beam when imposed with periodic vibration and shock is measured with fiber-optic sensor and piezoelectric sensor. The behaviors of the coupling fiber-optic vibration sensor are closely in accordance with high precision piezoelectric sensor. Experimental results indicate that the coupling fiber-optic vibration sensor has favorable vibration detection capability; it can meet the requirement of vibration measurement.