Kilo-Watt high-power Yb fiber laser at 1117 nm

We report a 1kW, 14 μm-MFD, Yb fiber laser operating at 1117nm, without any parasitic lasing at shorter wavelengths, and negligible intra-cavity Raman gain at longer wavelengths (>50dB extinction at 1175nm). To the best of our knowledge, this is the first experimental demonstration of 1kW output at 1117nm from an Yb fiber laser. In contrast to the 14 μm-MFD of the gain fiber in this report, our previous records at 1117nm of 400W for an Yb oscillator and 450W for an Yb MOPA, were limited primarily by a 6 μm-MFD gain fiber.