Characteristics of femtosecond supercontinuum generation in a short tapered fiber with a few micrometer diameter waist

摘要

A theoretical and experimental study of femtosecond supercontinuum generation in short tapered fibers with micrometer diameter waist has been carried out. In our numerical model, an extended nonlinear Schroedinger equation that involves the parameters of dispersion coefficient and effective core area varying along the length of tapered fiber is used to describe the evolution of intense femtosecond pulses centred at 850 nm. As a result, the supercontinuum is generated due to enhanced nonlinear effects in a narrow waist; the octave spanning spectra are found in an optimum structure with only short waist length of 8.0 mm and diameter of 2 μm for an input average power of 100mW. Experimental verification using a femtosecond pulse from a Ti: sapphire laser is then made and compared with the numerical simulations.