Modeling of visible-extended supercontinuum generation from a tapered Ytterbium-doped fiber amplifier

摘要

Supercontinuum (SC) generation directly from a nonlinear fiber amplifier, especially from a nonlinear ytterbium-doped fiber amplifier, attracts more and more attention due to its all-fiber structure, high optical to optical conversion efficiency, and high average output power potential. However, the modeling of SC generation from a nonlinear fiber amplifier has been rarely reported. In this paper, the modeling of a tapered ytterbium-doped fiber amplifier for visible to infrared SC generation is proposed based on the combination of the laser rate equations and the generalized non-linear Schrodinger equation (GNLSE). Ytterbium-doped fiber amplifier generally cannot generate visible extended SC due to its pumping wavelength and zero-dispersion wavelength. However, appropriate tapering and four-wave mixing makes the visible extended SC generation from an ytterbium-doped fiber amplifier possible. Tapering makes the zero-dispersion wavelength of the ytterbium-doped fiber shift to the short wavelength and increases the dispersion matching. Four-wave mixing plays an important role in the visible spectrum generation. The influence of pulse width and pump power on the SC generation is calculated and analyzed. The simulation results imply that it is promising and possible to fabricate a visible-to-infrared SC with low pump power and flat spectrum by using the tapered ytterbium-doped fiber amplifier scheme as long as the related parameters are well-selected.