The Investigation On Properties Of Two Photonic Crystal Fibers

Photonic crystal is a new type of optical materials, because of the particular propertiesand the light can be almost perfectly controlled in it, PCF has been a focus in optical fiberarea in recent years．First, this paper introduces the background research,present research condition andsignificance of PCF. A lot of unusual properties of the photonic crystal fiber are describedbriefly, such as endlessly single mode, adjustable dispersion characteristics, highbirefringence, strong nonlinear. Common numerical analysis methods used for the study ofphotonic crystal fiber are introduced and compared, In this paper, the multi-pole methodand finite element method are used for theoretical research and numerical simulationanalysis of the optical fiber.A new type pseudo-butterfly photonic crystal fiber (PB-PCF) with high birefringenceand low loss was proposed and the distribution of the fundamental mode, birefringence,and confinement loss characteristics are analyzed by the multi-pole method. Numericalsimulations show that when air holes in cladding are only four layers, the birefringence ofnewly designed photonic crystal fiber is two orders of magnitude higher than theconventional high-birefringence fiber (~5x10-4) and reaching1.06x10-2at the wavelengthof1.55μm, while its confinement loss reached10-6dB/m. This paper also explores theproperties of fibers in more air hole layers. Consequently, when birefringence reaches2.045×10-2at1.55μm a ultra high loss ratio can be found between two polarization modeof PCF, which is a special characteristic for producing single-polarization single-modepolarization-maintaining(SPSM) PCF.Several novel photonic quasicrystal fibers(PQF) with ultra-flatted chromaticdispersion at a wide telecommunication window are presented. A double claddingstructure is introduced into the quasi-lattice photonic crystal. Based on the full vectorfinite element algorithm simulation software COMSOL, the dispersion properties ofphotonic quasicrystal fiber are analyzed. According to the numerical simulation results forthe PQF, we obtain positive, zero and negative dispersion-flattened PQF by adjusting the parameters in a wide band near1550nm.Dispersion-flattened fiber as the transmission medium in wavelength divisionmultiplexing communication system as well as the generation and transmission of thesoliton has many important applications in optical parametric amplification and optimizesthe performance of the non-linear devices.