Widely tunable 70-MHz near-infrared source of ultrashort pulses based on a mode-locked ytterbium laser and a photonic-crystal fiber

Soliton self-frequency shift in a highly nonlinear photonic-crystal fiber is shown to enable an efficient wavelength conversion of 100-fs 70-MHz output of a solid-state ytterbium laser, allowing the generation of sub-100-fs laser pulses with a central wavelength tunable from 1060 to 1400 nm In the single-soliton regime. laser pulses are efficiently converted into isolated wavelength-tunable bands, with a photon-number conversion efficiency of 82% achieved for ytterbium-laser pulses converted to a spectral band at 1125 nm supporting 35-fs transform-limited pulses. For high input powers, the ytterbium-laser pulses are coupled to multiple solitons inside the fiber, enabling efficient supercontinuum generation through involved soliton dynamics. [GRAPHICS] Central wavelengths of three frequency-shifted solitons at the output of a 30-cm piece of the 1.6-mu m-core-diameter PCF measured as functions of the average laser power (C) 2010 by Astro Ltd Published exclusively by WILEY-VCH Verlag GmbH & Co KGaA