kW-class fiber laser prepared using an alternative solution doping MCVD-technique

Summary form only given. The growing demand for high power fiber lasers and the need for higher and higher cw-output powers pose new challenges to fiber technologists. The fabrication of suitable low-NA fibers in the materials system of choice, Yb, Al, P-doped silica, is challenging. Hence, new, facilitating fabrication methods are required. In this contribution we report on fabrication principles of a promising alternative solution doping method - the so called all-solution doping method [1].The presented all-solution doping method is used produce step index low-NA fibers as well as specialty index profile fibers. Here a porous, undoped SiO2 layer is deposited on the inside of a substrate tube and subsequently impregnated using a solution containing aluminum, phosphorus and ytterbium. The respective ratios of the dopants can already be predetermined in the solution. Thus the ratios of the respective dopants can be adjusted straightforwardly as opposed to the state-of-the-art method. Preforms prepared with this method were drawn to fibers (22/450) and used within a MOPA setup.