Fiber-optic Strain Sensor Based On The Mach-zehnder Filter

No matter in the monitor of the large-scale construction engineering or the fine structure, the stress sensing is a very important part. As a kind of stress sensor, optical fiber stress sensor has increasingly displayed its great vitality and broad development prospect. Because of the advantage of not being affected by the undulation of optical intensity and being easy to form WDM, the optical fiber sensor bases on wavelength encoding showing itself from optical fiber sensor.In this paper, a kind of fiber stress sensor based on Mach-Zehnder fiber filter is proposed, which is based on wavelength encoding. Two sensing patterns are studied, which are one channel pattern and several channels pattern, and the two patterns of one channel pattern are discussed, which are one arm of the Mach-Zehnder filter being affixed to the cantilever and both the two arm being affixed to the cantilever, and the several channels pattern is a small WDM system. In this paper, the stress sensitivity of Mach-Zehnder fiber filter is analyzed in theory, and the factors that affect the stress sensitivity are analyzed. Based on the study in theory, the optical circuit is established and the flexibility of this subject is verified in experiment, and then the factors which have influence on the result of experiment are analyzed.