Lasers emitting in the visible spectral range are of interest for various applications, e.g. in life sciences. Fiberbased setups of such lasers are highly desirable owing to their compactness and alignment-free operation but have only been reported for fluoride fibers or polymer fibers doped with dyes. While fluoride fibers are more difficult to manufacture and to handle in comparison to fused silica fibers, laser-active dyes implemented in a polymer matrix degrade after few hours of laser operation [1, 2]. Multiphonon quenching is the dominating mechanism preventing the usage of rare-earth dopands such as Praesodymium and Samarium in fused silica hosts.