Optimization and characterization of a femtosecond tunable light source based on the soliton self-frequency shift in photonic crystal fiber

Abstract

ABSTRACT We take advantage of the Raman soliton self-frequen cy shift experienced during the propagation in an a nomalous dispersive photonic crystal fiber in order to conti nuously tune the central frequency of ultrashort pu lses. We discuss the fiber properties to be favored to obtain high power spectral densities and we carry out an extensive e xperimental study of the properties of the frequency shifted pulses in t erms of spectral, autocorrelation, and RF spectrum measurements. Keywords: temporal solitons and pulse propagation, Raman sca ttering, photonic crystal fiber. 1. INTRODUCTION Nonlinear optics in fibers provides a very wide pan el of attractive solutions in order to generate new optical spectral components: self-phase modulation, four wave mixing , Raman Stokes generation or intrapulse Raman scatt ering 1 . This latest phenomenon leads to a progressive shift towa rds lower frequencies of the central frequency of u ltrashort pulses propagating in an anomalous dispersive fiber. There fore this effect known as the Raman soliton self-fr equency shift (SSFS)