Er:YAG fiber-shaped laser crystals (single crystal fibers) grown by micro-pulling down: Characterization and laser operation

Er3+ doped Y3Al5O12 (Er:YAG) single crystal fibers, with a diameter of 800 μm and a length up to 80 cm, were grown by the micro-pulling-down technique. The structural and optical characterization of these fibers shows a perfect single crystalline structure and a very high optical quality suitable for laser operation. With 6 cm long samples, we demonstrated a continuous wave laser delivering an output power of 950 mW for a pump power of 36 W coming from fiber-coupled laser diodes emitting at 1532 nm. To our knowledge, this is the first laser ever achieved with directly grown Er:YAG single crystal fibers.