Design And Study On The Characteristics Of Birefringence Photonic Crystal Fiber

In recent years, photonic crystal fiber (PCF) has become more attractive because of their unique properties, such as high birefringence and polarization maintaining, singular dispersion characteristics, high nonlinearity, surface enhanced Raman Effect, large mode area and so on. PCF is a kind of novel optical fiber structure, which has revolutionized fiber optics and attracted extensive attentions.To begin with, a kind of dual-core high birefringence and high coupling degree PCF is proposed in this paper. The characteristics of the dual-core PCF are analyzed by multipole method and mode coupling theory. Compared to traditional dual-core PCF, it is found that the birefringence and the coupling intensity increase with the increase of air-filling fraction. Therefore, the kind of dual-core PCF combines the high birefringence and high coupling degree together successfully. The birefringence reaches 10-2 order of magnitude. The kind of dual-core PCF is helpful for the manufacture of minitype photonic apparatus.Secondly, a kind of improved high birefringence PCF is proposed. The characteristics of birefringence, dispersion and leakage loss are studied by multipole method. Numerical results show that the improved PCF possess the properties of a flat dispersion. Moreover, the modal birefringence increases greatly as compared with the original PCF, and the leakage loss is about 104 times smaller than that of original PCF because the modification gives rise to the strong confinement of modes. It is expected that the improved PCF can be used as high birefringence and dispersion flattened fibers.Finally, we study the pulse propagation in birefringence PCF. We use lead silicate glass material SF6 in this paper, which is different to the former birefringence PCF, and obtaining ultra-flat supercontinuum from 1200-2000nm. Supercontinuum has great significance for nonlinear optics, ultra-short pulse generation, spectrum analysis, optical coherence tomography, optical metrology, optical communication, optical frequency comb, and so forth.