Study On The PZT Phase Modulator Of The Interferometric Fiber Optic Sensor System

Compared with traditional five conventional non-destructive testing technology, acousticemission detection technology is still a new technology, there is its own place in the detectiontechnology stage. Owing to the advantage of initiative, monitor integrity and so on, fiber opticsensor has many advantages contracted with many other traditional sensors. People had beenpaid attention to it for a long time. Based on the comparative advantages of opticalinterferometry technology and acoustic emission detection technology, a new researchdirection--fiber optic acoustic emission detection technology was born.PZT phase modulator have extensive application in the process of fiber optic acousticemission signal detection. This article introduces five different fiber optical interferometerstructure, study and analysis phase modulation technique and theoretically.Deduced to therelationship between the external applied voltage of PZT and the variation of light phase inthe optic fiber.Selected appropriate circular column PZT phase modulator and optic fiber,Used the Fast Fourier transform of Matlab to study the feasibility of small signal and bigsignal in theory. Constructed two different fiber optic acoustic emission system, andcompared with the linear fitting function of the experiment result and the linear function oftheoretical derivation, meanwhile analysised the reason of different results.In the practical application of fiber optic acoustic emission detection technology, phasedrift, frequency multiplication and the other disturb generate in the process collecting thesignal. Designed a feedback circuit, which composed five parts: photoelectricity circuit,amplifying circuit, low pass filter, integrating circuit and band-pass filter. Finally, proved thecircuit can improved the stability of the detecting system substantially.