RAMAN AMPLIFICATION AND SUPERCONTINUUM GENERATION IN PHOTONIC CRYSTAL FIBER

Abstract

Photonic Crystal Fibers are single material optical fibers with an array of periodic array of air holes running down its entire length. By leaving a single lattice site without an air hole, a localized region, which has a higher refractive index than the rest of the structure, will be formed. These fibers are being in active research because of its unusual & attractive optical properties like single mode operation in wide wavelength range, large mode area, excitation of non-linear effects at small mode area, and manageable dispersion properties etc. which are not achieved in standard silica glass fiber. Non-silica glasses such as telluride, fluoride and chalcogenide glasses have been used for formation of PCF because of its excellent optical transparency in the longer wavelength infrared (IR) region. In this project, we present the raman gain characteristic and Supercontinuum generation (SCG) in non-linear photonic crystal fibers (PCFs) by using the RSOFT(optisim) software. To design the nonlinear PCF here we considered the new material i.e. telluride glass. The nonlinear refraction coefficients n2 of telluride glass is 42 times higher than that of silica. The variation of effective index of guided mode and dispersion with wavelength in hexagonal lattice telluride glass PCF is calculated by using finite element method (FEM). The raman gain characteristics of Telluride PCF is calculated by using Rsoftoptisim software. We also compare the gain characteristics of telluride glass PCF with conventional silica PCF and find out that the Raman gain in Telluride PCFs can be highly improved than silica PCF. For SCG I reproduce the result of Dudley et al. (2006) with the help of RSOFT Optisim software and also show the effect of varying the power and pulse width on the bandwidth of the spectra.