Preparation of Er:YAG Crystal-Derived All-Glass Silica Fibers For a 1550-nm Single-Frequency Laser

YAG crystal-derived all-glass silica fibers (YDSFs) with different doping concentrations of Er
³⁺
were fabricated using the molten-core method. A maximum gain coefficient of 1.46 dB/cm was obtained when an Er:YAG rod at a doping concentration of 5 at.% was used as the precursor material. To the best of our knowledge, this is the highest gain coefficient at the 1.5-μm band in similar YDSFs. The diffusion between the Er:YAG core and silica cladding was investigated during the whole preparation process. Based on the homemade Er
³⁺
-doped YDSF, a 1.55-μm pulsed single-frequency YDSF laser was demonstrated for the first time, delivering an output power of 24.2 mW when the absorbed pump power was 174 mW. The corresponding slope efficiency was 15.1%. A single-pulse energy of ~32.7 nJ was obtained with a pulse duration of 78 ns and a repetition rate of 739 kHz. The signal-to-noise ratio was higher than 75 dB.