Theoretical And Experimental Study Of Acoustic Emission Monitoring Based On Optical Fiber M-Z Interferometer

Acoustic emission technology has been used in non-destructive testing, earthquake forecast, concrete monitoring, stress measurement, tiny displacement measurement and so on. The main characteristic of optical fiber sensor is high sensitivity, wide bandwidth and small bulk. The target of this paper is to combine theoretic analysis of acoustic emission monitoring with interferometric optical fiber sensor technology to study the feasibility which to excogitate a new interferometric optical fiber acoustic emission sensor monitoring system.This paper gives the structure and principle of interferometric optical fiber acoustic emission sensor with "n" configuration based on optical fiber Mach -Zehnder interferometer and analyses the interacting between optical fiber sensor and acoustic surface wave in theory. The experimental results make know that the sensitivity of this optical fiber acoustic emission sensor is proportional to the effective length of optical fiber and number of sensor. At the same time, the good direction difference of this sensor is found via experiment. So this interferometric optical fiber acoustic emission sensor is fit for beamed monitoring of acoustic surface wave in industry.