2 W Single-Mode Visible Laser Oscillation in Pr-Doped Double-Clad Structured Waterproof Fluoro-Aluminate Glass Fiber

Visible lasers have many applications, such as, optical storage, display technologies, medicine, and flow cytometry. Especially primary visible solid-state laser (PVSSL) is a very attractive fundamental laser source of UV laser by second harmonic generation (SHG), because such UV laser source is expected to be higher conversion efficiency than typical UV laser system with third or fourth harmonic generation technique with twice nonlinear conversion process. Recently, fundamental visible laser researches have been increasing and the power also becomes enough large for applications. We have been developing visible fiber lasers based on Pr-doped waterproof fluoride glass fiber (WPFGF) [1], and the power progressed remarkably and reached over 1.0 W in red, green and blue colors [2]. Since then we developed a double-clad (DC) structured fiber [3], the fundamental visible fiber laser becomes a promising item to build a new UV laser system. In this paper, we report a 2 W single-mode laser oscillation in Pr:DC-WPFGF.