Design Of New Birefringent Photonic Crystal Fibers

In the early 1990 s, Photonic Crystal Fibers(PCFs) was first proposed. Then, many pioneering experimental works showed that PCFs can overcome many limitations of traditional fiber with unprecedented optical properties,including endlessly single-mode transmission, having anomalous dispersion and high nonlinear in the visible region, and therefore it have been attracting the interests of scientists all over the world. Among the many unique properties of PCFs, birefringence characteristics which have a very important research value become a hot topic in the field of photonic crystal fiber in recent years.This thesis focuses on mode properties of two polarization states of a new highly birefringent photonic crystal fiber and a single-polarization single-mode dual-core photonic crystal fiber based on resonant coupling method, the main contents are as follows:Propose a simple structure of high birefringence photonic crystal fiber, and theoretically study its optical properties, including birefringence, confinement loss, dispersion, mode field area and nonlinear. Based on full vectorial Finite Element Method, Numerical results have shown that the optical fiber has 10-2 order of high birefringence and less than 1d B/km of confinement loss. By adjusting the structure parameters reasonably it can obtain large negative polarization mode dispersion of-472ps/km?nm. Meanwhile, the nonlinear coefficient is up to 120 km-1W-1.Secondly, based on the resonant coupling theory, an optimized single-polarization single-mode optical fiber with operating wavelength range of 1.4-1.7μm is proposed. While the confinement loss is less than 10-3d B/km in the low-loss core and up to 100 d B/km in the high-loss core. In addition, the bending loss characteristic of the photonic crystal fiber is studied by the Beam Propagation Method.