利用小功率40 kHz的CO2脉冲激光对25 μm厚的超薄熔石英玻璃与熔石英毛细管端面进行热熔焊接，研究和分析了占空比(脉冲激光功率)、离焦激光预热、离焦激光退火对熔石英玻璃热熔焊接的影响。结果表明，实现超薄熔石英玻璃与毛细管端面无气化穿孔、密封、牢固焊接的占空比为37%；占空比为20%的+2 mm离焦脉冲激光预热对超薄熔石英玻璃无裂纹/裂缝的焊接起到了关键作用；适当占空比的-2 mm离焦脉冲激光退火能够释放超薄熔石英玻璃在热熔焊接过程中产生的残余热应力，提高熔石英器件的性能，经激光焊接的光纤法布里珀罗传感器的压力和温度曲线的线性度分别为0.9995和0.9991，而且重复性好。

The study on the heating fusion welding between the ultra-thin fused silica glass with 25 μm-thickness and the end face of the fused silica capillary tube is carried by using low power CO2 pulse laser with a pulse frequency of 40 kHz. The duty ratio, the defocus laser preheating and the defocus laser annealing impacting on the heating fusion welding of the fused silica glass are researched and analyzed. The results show that a duty ratio of 37% can perform perfectly the no penetration, sealing and firm welding between the ultra-thin fused silica glass and the fused silica capillary tube. For the welding without crack or split of the ultra-thin fused silica glass, the preheating of the +2 mm defocus pulse laser with a duty ratio of 20% plays a key role. The annealing of the -2 mm defocus pulse laser with an appropriate duty ratio can release the residual thermal stress produced in the process of the heating fusion welding in the ultra-thin fused silica glass, enhancing the performance of the fused silica device. The pressure and temperature linearity of the fiber-optic Fabry-Pérot sensor welded perfectly by the CO2 laser are 0.9995 and 0.9991, respectively, and their repeatabilities are good.