1.5-kW Yb-Raman Combined Nonlinear Fiber Amplifier at 1120 nm

Abstract

A high power Yb-Raman combined nonlinear fiber amplifier employing dual-wavelength seed is demonstrated. The amplifier is seeded by 1070- and 1120-nm signal lasers simultaneously. The mechanism of power evolution of the two signals along the gain fiber is analyzed. By careful design and optimization of the amplifier, we make sure the 1120-nm signal extract majority of the gain in the amplifier. In the end, 1.52-kW 1120-nm laser is obtained with an optical efficiency of 75.6%, which is the highest power ever reported near this wavelength. The compact and efficient amplifier scheme proposed in this letter can be employed for high power amplification of 1100-1200-nm lasers.