Polarization Maintaining Highly Nonlinear Photonic Crystal Fiber

Recently, the research on photonic crystal fiber (PCF) has aroused great concern worldwide. In the past decades, the theoretical analysis and preparation method of PCF has are constantly emerging, as well as new PCF device. Compared with conventional optical fiber, PCF has advanced features. For instance, its birefringence can be orders of magnitude more than traditional polarization-maintaining optic fiber. Moreover, PCF is with large value of nonlinearity and therefore some nonlinearity effects can be realized only in PCF rather than conventional optical fiber. In this thesis, we theoretically analyze the optical transmission character of high birefringence photonic crystal polarization maintaining optic fiber and highly nonlinear PCF. The numerical simulation is also presented. The results are as follows:(1)A new type of poly methyl meth acryl ate (PMMA) single polar single mode microstructure polymer optical fiber is designed. And the polarization character and constraint loss of this new PCF are analyzed by all-vector finite element method and beam propagation method. By optimizing the parameters of fiber structure, we found that in the visible wavelength range, this new type microstructure fiber can only transmit one polarization mode of fundamental mode due to the cut-off wavelength difference between two orthogonal polarization modes, which can realize single polarization single-mode operation. The confinement loss at 0.57μm of the 11 hex arrangement fiber structure polarization mode is only 1.13dB/Km.The low loss single polarization single mode microstructure polymer fiber can be used to eliminate intrinsic polarization crosstalk and polarization mode dispersion existed in traditional polarization fiber.(2)A highly nonlinear photonic crystal fiber is designed and the theoretical analysis and numerical simulation of its character are realized by all-vector finite element method. The results show that in the wavelength range of 0.7-1.4μm,the dispersion can be tuned by adjusting the optical fiber structure and nonlinear coefficient reaches to 51 km-1W-1 at the wavelength of 1.31μm.