Long-period Fiber Grating Fabricated By Arc Tapering

This paper focused on systemic research on long-period fiber grating (LPG), and put forward a new LPG fabrication method. It is implemented by arc tapering, via arc tapering function of a optical fiber fusion splicer, and use mobile platform for period control. It was proved that a LPG fabrication will come to a success by arc tapering for 20 times or less. This method has advantages below: tiny cost, simple experiment instrument needed, brief operation, and good stability. At the same time, different types of parameter that affects the characteristic of long fiber grating's spectra are systematically analyzed emulated. The main content of this paper includes: basic theory of fiber grating, modal theory and mode-coupling of LPG, coupling characteristics and emulation and environmental characteristics of LPG, and the experiment which fabricate LPG by arc tapering method. The main achievements of this paper are as follows:(1) This paper took a deep introduction to current situation of LPG from 3 parts: researches on theories, preparations, and applications.(2) The mode-coupling equations of informal optical wave guide were derived, took theoretical analysis and emulation on modes in LPG via three-layer fiber grating model. In the other hand, model-coupling characteristics of LPG (mode-coupling between fundamental mode and coupling modes) were particular analyzed and emulated, including effective refractive index, propagation constant, coupling constant, waveguide dispersion factor, etc. And put on numerical calculation of LPG's transmission spectrum. Furthermore, this paper researched on environmental characteristics of LPG, including sensitivity factors such as temperature, strain, refractive index of environment, etc.(3) LPGs were fabricated by arc tapering method. The feasibility and stability of the fabrication system and fabrication method were proved, and then took analysis to fusion parameters which would affect the fabrication result. The experiment results reach the expected requirements and show guiding significance to LPG's arc tapering fabrication and future work.