Sensing characteristics study of fiber Bragg grating for nonlinear ultrasonic

Ultrasonic defect detector which is based on linear ultrasonic technology has been widely applied in structural health monitoring now. However, its detection sensitivity is not high enough. Nonlinear ultrasonic method was proposed to improve it. On the other hand, fiber Bragg grating technology is being developed rapidly in sensing field and it has great advantage in distributed measurement. In this paper, a new system which combined nonlinear ultrasonic and fiber Bragg grating was built. The influences of some important parameters were discussed. The results proved the system can detect defect effectively and can realize distributed measurement easily.