演講摘要：

Mid-infrared fiber laser sources are beneficial for a broad range of applications, including scientific research, industry, biomedicine, etc. In recent years, 2μm band thulium-doped fiber laser has become more and more maturing, but the fluoride fiber laser with wavelength >2μm is still a hot research topic due to the limitations of key technologies and devices. Our research group has carried out corresponding work in thulium-doped fiber lasers，2.8μm and 3.5μm erbium-doped fluoride fiber lasers and their applications. Thulium-doped fiber laser: 2μm nanosecond and picosecond pulses were achieved by Q-switching and mode-locking technology and as a seed source, the pulses were amplified to over 100 watts by all fiber thulium-doped fiber amplifier. A mid-infrared supercontinuum (1.9 -4.1μm) was obtained with the output power of 10.67W pumped by a picosecond thulium-doped fiber laser and a 3.5μm erbium-doped fluoride fiber laser was achieved pump by a wavelength tunable thulium-doped fiber laser. In addition, we have achieved the transparent polymer welding without any absorber by the thulium-doped fiber laser. Fluoride fiber laser: Based on WSe2 saturable absorber mirror, a 2.8 μm mode-locked Er3+:ZBLAN mid-infrared fiber lasers were realized with an average output power of 360 mW, a repetition rate of 42.43 MHz, and a pulse duration of 21.26 ps. And we pump a segment of Er3+:ZBLAN fiber in a linear cavity oscillator by utilizing a home-made 2μm tunable fiber laser and a 973 nm laser diode. A continuous laser output with a center wavelength of 3456.3nm, a spectral width of 0.2nm, and a maximum output power of 781mW is achieved. Besides, our group has also tackled some key problems of mid-infrared fiber lasers such as the fusion splice technology of the soft glass fiber. We have achieved the fusion splice between ZBLAN fiber and ZBLAN fiber, ZBLAN fiber and silica fiber, passive ZBLAN fiber and chalcogenide fiber. And, in order to solve the influence of the fiber end reflection on the fiber laser system, we have also realized an AlF3 fiber-based end cap for a mid-infrared fiber laser. 中紅外激光器在前沿科學(xué)研究、生物醫(yī)療、工業(yè)應(yīng)用、環(huán)境監(jiān)測、紅外成像、光電對(duì)抗等諸多領(lǐng)域有著重要應(yīng)用。近年來，2微米波段摻銩光纖激光器逐漸成熟，但波長>2 微米的氟化物光纖激光器由于關(guān)鍵技術(shù)及器件等問題的限制，仍為研究的熱點(diǎn)問題。課題組在2摻銩光纖激光器及其應(yīng)用、2.8μm及3.5μm摻鉺氟化物光纖激光器等方面開展了相應(yīng)的工作，并取得了一定的進(jìn)展。 摻銩光纖放大器方面：采用調(diào)Q及鎖模等方式分別實(shí)現(xiàn)了多種納秒、皮秒量級(jí)2微米激光脈沖輸出，并分別對(duì)其進(jìn)行功率放大，實(shí)現(xiàn)了平均功率達(dá)百瓦的激光輸出；并將其作為泵浦源，實(shí)現(xiàn)了1.9-4.1μm，10.67W超連續(xù)譜輸出及3.5微米氟化物光纖激光輸出；此外，采用摻銩光纖激光器也實(shí)現(xiàn)了無吸收劑的透明聚合物焊接。 在氟化物光纖激光器方面：采用自行開發(fā)的WSe2可飽和吸收鏡，結(jié)合摻鉺氟化物光纖，實(shí)現(xiàn)了中心波長2.8 μm、平均輸出功率360 mW、脈沖寬度21.26 ps、重頻42.43 MHz的鎖模脈沖輸出；結(jié)合自行研制的2 μm可調(diào)諧光纖激光器及973 nm半導(dǎo)體激光器，對(duì)摻鉺氟化物光纖進(jìn)行雙波段泵浦，在線形腔結(jié)構(gòu)下，實(shí)現(xiàn)了中心波長為3456.3 nm，功率為781 mW的連續(xù)激光輸出。 此外，課題組還在軟玻璃光纖熔接等中紅外光纖激光器核心技術(shù)方面進(jìn)行了一定的研究，實(shí)現(xiàn)了氟化物光纖和氟化物光纖、氟化物光纖和石英光纖、無源氟化物光纖和硫化物光纖之間的熔接；也實(shí)現(xiàn)了中紅外光纖激光器所用的AlF3光纖“端帽”。