【作者】 李楠；

【导师】 秦冠仕；

【作者基本信息】 吉林大学 ， 微电子学与固体电子学， 2017， 博士

【摘要】 2μm超短脉冲光纤激光器具有脉冲宽度窄、峰值功率高、频谱范围宽等特点,在基础科学研究、生物医疗、材料加工、环境监测、军事等方面有着重要的应用。宽调谐2μm超短脉冲激光作为该波段光纤激光器发展的一个重要方向,一直是该领域的研究热点。在众多的波长调谐技术中,全光纤多模干涉滤波器具有结构紧凑、与光纤兼容等特点,备受研究者们关注。但目前,基于多模干涉滤波器的全光纤宽调谐2μm超短脉冲激光器未见报道。另外,在2μm超短脉冲激光的应用方面,尤其是中红外超连续谱产生研究方面,由于2μm激光的波长处于中红外波段,所以其在获得高转换效率的中红外超连续谱方面有一定的优势。但在高相干性中红外超连续光源研究方面,国内外报道甚少。针对上述问题,本论文围绕2μm超短脉冲光纤激光器的波长调谐技术以及基于2μm超短脉冲激光获得高相干性的中红外超连续光源等方面进行了系统的研究,取得了以下研究结果:(1)利用自制的具有多个透射峰的全光纤多模干涉滤波器,采用弯曲多模光纤的方法,首次实现了波长调谐范围覆盖1919.6~2014.9 nm的全光纤锁模激光器。该实验证明了采用多模干涉滤波器可以实现全光纤宽调谐锁模激光器。(2)利用拉曼孤子自频移技术获得了波长调谐范围覆盖1611~1984 nm的全光纤超短脉冲激光器。在实验中,所用的泵浦源为1560 nm飞秒脉冲光纤激光器,所用的非线性介质为10 m长的高非线性石英光纤,通过优化泵浦源和高非线性光纤参数获得了宽调谐拉曼孤子激光输出。(3)采用啁啾脉冲放大技术获得了平均功率为2.1 W,脉冲宽度为170 fs的2μm超短脉冲激光输出;进一步利用其作为泵浦源,采用自制的拉锥氟碲酸盐微结构光纤作为非线性介质,首次获得了高相干性、波长范围覆盖1.4~4μm波段的超连续光源。更多还原

【Abstract】 2 μm femtosecond pulse fiber lasers have wide applications in basic science researches,biomedicine,material processing,environmental pollution monitoring and military affairs because of their outstanding features of ultrashort pulse width,higher peak power and broader spectral range.The all-fiber widely tunable ultrashort pulse fiber lasers near 2 μm have attracted much attentions in recent years as an important branch in the filed of the fiber lasers.As for the diverse tuning devices,multimode interference filters(MMIFs)have many advantages such as high compactness,simple fabrication process and good compatibility with optical fibers.However,all-fiber widely tunable ultrashort pulse fiber lasers near 2 μm based on MMIFs have not yet been demonstrated.In addition,2 μm femtosecond pulse fiber laser has the advantage of obtaining higher conversion efficiency mid-infrared supercontinuum generation because of its longer wavelength in the mid-infrared.However,using 2 μm femtosecond pulse fiber lasers to achieve coherent supercontinuum generation is reported fewer.To solve above problems,the main works during the doctoral years were rsearching novel tuning techniques for 2 μm femtosecond pulse fiber lasers and using the 2 μm femtosecond pulse fiber lasers to obtain the coherent supercontinuum generation.Details are as follws:(1)A homemade MMIF with three main transmission peaks was used firstly to obtain a widely tunable mode-locked 2 μm fiber laser by the bending method.The tunable range of the mode-locked 2 μm fiber laser was 1919.6~2014.9 nm.Our results showed the designed MMIF could be used to construct all fiber widely tunable mode-locked lasers.(2)A widely tunable 2 μm ultrashort pulsed fiber laser with a tuning range of 1611~1984 nm was obtained by the Raman soliton self-frequency shift technology.In the experiment,a 1560 nm pulsed fiber laser as the pumped source,a 10 m long silica fiber with the high nonlinear coefficient as the nonlinear media,the widely tunable Raman soliton laser was achieved by optimizing the parameters of the pumped source and high nonlinear coefficient fiber.(3)A 2 μm femtosecond fiber laser with the 2.1 W average power and 170 fs pulse width was achieved from a Chirped Pulse Amplication(CPA)system.By using this 2 μm femtosecond fiber laser as the pump source,a fluorotellurite microstructured fiber(MF)as the nonlinear media,the coherent supercontinuum generation from 1.4 to 4 μm was obtained firstly.更多还原