Preparation of Ho(3+)/Tm(3+) Co-doped Lanthanum Tungsten Germanium Tellurite Glass Fiber and Its Laser Performance for 2.0 μm

Ho(3+)/Tm(3+) co-doped 50TeO(2)-25GeO(2)-3WO(3)-5La(2)O(3)-3Nb(2)O(5)-5Li(2)O-9BaF(2) glass fiber is prepared with the rod-tube drawing method of 15 μm core diameter and 125 μm inner cladding diameter applied in the 2.0 μm-infrared laser. The 2.0 μm luminescence properties of the core glass are researched and the fluorescence intensity variation for different Tm(3+) doping concentration is systematically analyzed. The results show that the 2.0 μm luminescence of Ho(3+) is greatly influenced by the doping concentration ratio of Ho(3+) to Tm(3+) and that the maximum fluorescence intensity of the core glass can be obtained and its emission cross section can reach 0.933 × 10(−21) cm(2) when the sensitized proportion of holmium to thulium is 0.3 to 0.7 (mol%). Simultaneously, the maximum phonon energy of the core glass sample is 753 cm(−1), which is significantly lower than that of silicate, gallate and germanate glass and the smaller matrix phonon energy can be conductive to the increase 2.0 μm-band emission intensity. The continuous laser with the maximum laser output power of 0.993 W and 2051 nm -wavelength of 31.9%-slope efficiency is output within the 0.5 m glass fiber and the experiment adopts 1560 nm erbium-doped fiber laser(EDFL) as the pump source and the self-built all-fiber laser. Therefore, the glass fiber has excellent laser characteristics and it is suitable for the 2.0 μm-band laser.