BLUE ENHANCED SUPERCONTINUUM GENERATION IN SPIRAL SILICA PHOTONIC CRYSTAL FIBER

Abstract

We present a design of a highly nonlinear silica spiral photonic crystal fiber and obtain the supercontinuum generation for a wider bandwidth (2300 nm) extending from 320 nm to 2620 nm at 40 dB below the spectral peak power using a 30 cm long designed fiber. We use 100 fs, 60 kW secant hyperbolic pulse as a pump at 532 nm wavelength. The nonlinear coefficient is 648.48 W-1 km-1 and group velocity dispersion is 20.75 ps2/km at the pump wavelength. The generated supercontinuum would be useful in optical coherence tomography, fluorescence imaging, and absorption spectroscopy. There has been an impressive progress in the development of photonic crystal fiber (PCF) over the last few decades. These fibres have tremendous potential in various domains such as nonlinear optics, telecommunications or medical science as the fabrication process allows for a great flexibility in the design of these fibers. Broadband supercontinuum light was demonstrated in 2000 using photonic crystal fiber. Latter the theoretical studies and sophisticated characterization techniques have evolved significantly over the years There is still ample scope of research for new fiber design and materials in order to get light sources in deep UV and mid-IR ranges. Some of these aspects are addressed in this dissertation