Design and construction of optical fiber sensor system for detection of stress and fine motion

Two main concepts in design and construction of stress and fine motion detection system using fiber optic sensor was included in this project. The first is design and construction concept using Intensity Modulation techniques using plastic multimode optical fiber (125μm dim) and has NA=0.27 with losses rate 2.1 db and directionality about 25 db, and we used He-Ne laser source (632.8 nm) with LLM-2 light power meter to detect the variation in output laser power due to micro-displacement for movement body under test. The second concept includes Modeling for laser beam tracking through fiber and that which reflected for mirror to detector. Variation in output power due to target movement was theoretical analyzed from study of variation of Gaussian front wave profile of using MATLAB program within displacement range from 0-5 mm. Non-linear relation between separated distance and beam intensity was investigated. Finally our design are evaluated in comparison with published research which is found compatible in theoretical and experimental results.