High-efficiency single-frequency DBR fiber laser at 1091 nm utilizing a Yb:YAG crystal-derived silica fiber.

A single-frequency distributed Bragg Reflector (DBR) fiber laser operating at 1091 nm was demonstrated by using a Yb:YAG crystal-derived silica fiber (YDSF). The YDSF was prepared via the molten core (MC) method, with a Yb2O3 doping concentration of 5.60 wt.% in the core, resulting in a gain coefficient of 1.45 dB/cm at 1091 nm. Employing 0.8 cm of the YDSF, we attained a single-frequency laser with a maximum output power of 145 mW and a slope efficiency of 31.8%. The laser exhibited an optical signal-to-noise ratio (OSNR) exceeding 71 dB, a linewidth of ∼34 kHz, and a stabilized relative intensity noise (RIN) at -132 dB/Hz for frequencies over 4.5 MHz. The fiber laser could serve as an outstanding seed source for high-power, narrow-linewidth fiber amplifiers operating at 1091 nm.

Single-frequency fiber laser of 315†mW at 1940†nm based on a Tm : YAG/Ho : YAG-co-derived silica fiber.

A 1940 nm single-frequency distributed Bragg reflector (DBR) fiber laser was demonstrated based on a Tm : YAG/Ho : YAG-co-derived silica fiber (THCDSF). The THCDSF, which had a core dopant concentration of 8.02 wt.% Tm2O3 and 1.18 wt.% Ho2O3, was prepared via the melt-in-tube (MIT) method using a Tm : YAG and a Ho : YAG as the precursor core and a silica tube as the cladding. Employing 1.8 cm of the THCDSF, we achieved a maximum single-frequency output power of 315 mW at 1940 nm when pumped by a 1610 nm fiber laser. The slope efficiency of the laser was 29.68% for the absorbed pump power. The laser linewidth was less than 23.65 kHz, and the relative intensity noise (RIN) stabilized at -145 dB/Hz after exceeding 4.8 MHz. To the best of our knowledge, this is the first demonstration of a single-frequency DBR laser with a Tm3+/Ho3+ fiber as the gain medium.