Supercontinuum Spectrum Generation in Tapered Fiber Using Femtosecond Laser Pulses

We present an extended nonlinear Schrödinger equation model that involves the dispersion coefficient and effective core area varying along the transition length of tapered fiber. The supercontinuum generated from short tapered fibers with a few micrometer diameter waist gives a good agreement with experiments of Teipel et al. and the modified stimulated Raman scattering formulation in our analysis is found to be effective. The spectral evolution along the tapered fiber is also investigated in order to gain insights into mechanism of the white light. In addition, the phase of supercontinuum pulse is calculated in some detail and shown along the propagation distance