Tm3+-doped silica glasses with molar fraction composition of 0.3Tm2O3-0.3xAl2O3-(100-0.3-0.3x)SiO2 (x=8, 10, 15, 20) denoted as ATS glasses are prepared by sol-gel method. The spectroscopic properties of the bulk glasses are investigated. The maximum emission cross section and measured fluorescence lifetime at 1811 nm are 6.39×10-21 cm2 and 645 μs, respectively. The lowest OH content is 10.5×10-6. The fiber preform was prepared by rod-in-tube method. The glass with composition 0.3Tm2O3-4.5Al2O3-95.2SiO2 is used as fiber core; the inner cladding is pure silica glass with an octagonal shape; and the outer cladding is ultraviolet curing layer. Laser properties of the fiber are investigated. The maximum laser output power reaches 1.23 W from a 66-cm-long fiber and the slope efficiency is 11.7%. The lasing threshold is 6.07 W and the lasing wavelength is centered at 1952 nm.