Characteristics Of Polymer Long-period Fiber Grating Sensor

In this paper, we presented a research of the sensing characteristics of polymer Long period grating (LPG) and its inscribing.First of all, based on Coupled-Mode Theory (CMT) and simplified 3-layered model of step-index single-mode optical fiber, we analyzed theoretically and simulated some special characteristics of LPG . We analyzed in detail about axial strain temperature and transverse pressure sensitivity of polymer LPG.We analyzed theoretically and computed numerically the transmission spectrum of azo-benzene doped POF LPG.Then we tested the photosensitivity of POF whose core material was copolymer of azo-benzene and poly (methyl methacrylate) (PMMA) in experiment.We also measured the photoinduced refractive index change of thin films containing core material with different concentration. We inscribed surface relief grating on the thin films using Point-by-Point method and Amplitude Mask method (the amplitude mask was taken place by grating roll film manufactured by ourselves).At the end, we built experimental installation for inscribing polymer LPG. using point-by-point method.