High Power Specially-Designed Fiber Laser Operating At 1018 Nm Using 20/400 Mu M Ytterbium-Doped Fibers

In recent years, ytterbium-doped fiber lasers operating at around 1018 nm have attracted considerable interest for their capability to be used as the pump source in multi-kilowatt fiber lasers [1–3]. There are several challenges to realize the high power 1018 nm fiber laser, the most prominent is suppressing the amplified spontaneous emission (ASE) at the range of 1030–1060 nm. In this paper, we report our experimental results of a high power specially-designed amplifier (SDA) at 1018 nm by employing a low core/cladding diameter ratio active fiber of 20/400 μm.