| The fundamental properties of microstructure fiber (MF) are investigated in this dissertation; moreover, the characteristic and application of this new type of fiber in the field of fiber grating are theoretically and experimentally discussed. Beginning with the MF's status quo, the novel properties of microstructure fiber are summarized in the following parts. Then the theoretical computing methods are presented, in which we emphasize particularly on the plane wave method (PWM) and the finite element method (FEM). With the two methods mentioned above, important parameters such as bandgap, dispersion, leaky loss and so on are calculated, as well as the birefringence of two kinds of MF, which are in two different mechanisms. A new type of optical coupler based on dual-core bandgap microstructure fiber is presented. Furthermore, fiber Bragg grating are successfully inscribed in grapefruit MF, and the characteristic of the individual resonant peaks are analyzed, based on which a multi-wavelength fiber laser is demonstrated. The details are described as follows:1. The guided properties of MFs are investigated. Firstly, we study the photonic band structure of the MFs, which have air holes in cladding arranged in the figure of triangular and honeycomb. Then the guided mechanisms of MFs are demonstrated, and waveguide dispersion, leaky loss and effective modal area for both index-induce MF and PBGF are calculated.2. On the basis of studying fundamental properties of MFs, the birefringence properties of form-induced and stress-induced HiBi-MFs are investigated. The group birefringence and the phase birefringence of the two fibers are demonstrated and the numerical results are in agreement with the reported experimental results.3. The dual-core air-guided photonic bandgap fiber couplers are designed and decoupling phenomenon has been found. Coupling properties of the PBGFs with two adjacent air holes as fiber cores are analyzed. The decoupling point, where there is no... |
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