%0 Journal Article
%T Highly Nonlinear and Birefringent Spiral Photonic Crystal Fiber
%A S. Revathi
%A Srinivasa Rao Inbathini
%A Rizwan Ali Saifudeen
%J Advances in OptoElectronics
%D 2014
%I Hindawi Publishing Corporation
%R 10.1155/2014/464391
%X We propose and design a spiral photonic crystal fiber with elliptical air holes for achieving high birefringence, large nonlinearity, and negative dispersion. The structure is designed using chalcogenide glass (As2S3) for different ellipticity ratios of air holes in the cladding and the effect on various properties is observed. The proposed structure has birefringence of the order 10£¿2, nonlinearity of 26739.42£¿W£¿1£¿m£¿1, and dispersion of £¿1136.69 at 0.85£¿¦Ìm. An accurate numerical approach based on finite element method is used for the design and simulation of the structure. Due to high birefringence and negative dispersion, the proposed structure can be used for polarization control and dispersion compensation, respectively. 1. Introduction Photonic crystal fiber is a class of optical fiber which is based on the properties of photonic crystal. Due to its unique properties photonic crystal fiber finds a lot of applications in optical fiber communication [1]. In standard fiber, the guiding mechanism is by a region with higher refractive index than the surrounding cladding. In case of PCFs, the microstructure of core and air holes surrounding it provide the required index difference. The basic principle of operation of a PCF is based either on modified total internal reflection in which light is guided in solid core which depends on the relative refractive index difference between the core and the microstructure cladding or on photonic band gap effect in which light is confined by a photonic band gap that is created by the microstructure cladding [2¨C4]. Such fiber allows the propagation of light through lower index core or even through hollow core. Compared to conventional fiber, PCFs provide large freedom in the design which allows the flexibility in various properties including birefringence, flattened and negative dispersion, effective area, and nonlinearity. Apart from the conventional hexagonal lattice, different types of air hole arrangements are proposed for achieving many useful properties [5¨C7]. In equiangular spiral photonic crystal fiber, the air holes are distributed around the solid core so that the arrangement gives a spiral pattern. The design parameters for spiral PCF include number of spiral arms, number of air holes in each spiral arm, and core diameter. Various useful properties can be obtained by tailoring these parameters to the PCF design. Equiangular spiral PCF (ES-PCF) with small effective area and large nonlinearity has been reported [8]. Spiral PCF with elliptical core is designed [9] which has large birefringence and
%U http://www.hindawi.com/journals/aoe/2014/464391/