High-power Near-Infrared Supercontinuum Source Generated in an Ytterbium-Doped Fiber Amplifier

A supercontinuum source with larger than 200 W average power covering 1 mu m to beyond 1.7 mu m is constructed in a four-stage master-oscillator power-amplifier (MOPA) configuration. The process of power amplification and spectral evolution during supercontinuum generation and the influence of pulse duration on this process are investigated. For the signal light in normal dispersion region, Raman effect plays dominant role in the first phase and the power transfer from amplified signal light to long wavelength region can be substantially achieved. When the spectrum is extended across the zero dispersion wavelength, soliton effect becomes the main effect for spectral broadening and the power transfer efficiency is lower to make the signal light a high peak. With similar average output power, narrower seed pulse leads to higher peak power and can induce Stokes waves earlier which leaves longer fiber for soliton propagating. Thus the spectrum can be shifted to longer wavelength. However, the signal light becomes a higher spike. In a word, narrower seed pulse leads to higher signal peak and wider SC source.