Femtosecond Pulse Trains through Dual-Pumping of Optical Fibers: Role of Third-Order Dispersion

Generation of high-repetition-rate, femtosecond, soliton pulse trains through dual-wavelength pumping of a dispersion-decreasing fiber is studied numerically. The achievable shortest pulse width is found to be limited by third-order dispersion that has a significant effect on the pulse-compression dynamics. The output wavelength is red shifted because of intrapulse Raman scattering and depends heavily on third-order dispersion, whose positive values lead to the most red shifted solitons (>25% of the input pump center wavelength). The proposed scheme allows the generation of ultrashort pulse trains at tunable high repetition rates with a wide range of output wavelengths and pulse durations through dispersion engineering. The resulting frequency combs extend over a wide bandwidth with a tunable spacing between the comb lines.