A Study Of Optical Property Measurement For Fiber Grating Based On White Light Interferometry

As a new type of all-fiber passive component, the fiber grating is agrating structure,the refractive index changes periodically along the core. Based onthe photo-induced refractive index change effect of fiber material, fiber gratings canbe given by UV laser through side writing technique. Because of many advantage,such as high sensitivity, good linearity, light weight, low volume,anti-electromagnetic interference, distributed measurement, fiber grating has beenwidely used in fiber sensing system and optic communication. As the fiber gratingapplication and field continue to expand, fabrication technique continue to improve,the requirement to test fiber grating characterization is so urgent, there will be greatvalue to develope a high resolution measurement technique and system. White lightinterferometry is a good technique to measure the spatially resolved parameters inthe optical device,with its advantage of high resolution and sensitivity. This thesisshows that white light interferometry has huge potential when it used in themeasurement of fiber grating spectra and profile. This thesis mainly focused onfollowing aspect:1.Analyze the internal relation between fiber grating refractivemodulation,length and spectra based on coupled-mode theory,show refractivemodulation and length have influence on fiber grating spectra.Introduce fiber gratingreconstruction theory,and show the principle and procedure of integral layer peelingalgorithm,finally test and verify its accuracy.2.Show the basic principle and data processing method of measuring fibergrating reflectivity by white light interferometry.The reflectivity measuring system isestablished,and explain the crucial component,introduce the optical path adjustingskill, finally give the spectral resolution formular and operating parameter of thesystem.3.To manufactory a high reflectivity fiber grating for the experiment,analysisthe measurement of fiber grating length and refractive index profile,executeexperiment and analyze experiment result,which confirmed that the system is feasible.