基于PbS量子点的可调谐高能量锁模光纤激光器  

Tunable high-energy mode-locking fiber laser based on PbS quantum dots

作　　者：陈广伟 赵悦 胡国庆 秦莹 贾凯琳 陈丽 李慧宇 贺敬文 周哲海[1,2] Chen Guangwei;Zhao Yue;Hu Guoqing;Qin Ying;Jia Kailin;Chen Li;Li Huiyu;He Jingwen;Zhou Zhehai(Key Laboratory of Modern Optoelectronic Measurement Technology in Mechanical Industry,Beijing Information Science and Technology University,Beijing 102206,China;Key Laboratory of the Ministry of Education for Optoelectronic Measurement Technology and Instruments,Beijing Information Science and Technology University,Beijing 102206,China;National Physical Experiment Teaching Demonstration Center,Beijing Jiaotong University,Beijing 100044,China)

机构地区：[1]北京信息科技大学机械工业现代光电测试技术重点实验室,北京102206 [2]北京信息科技大学光电测试技术及仪器教育部重点实验室,北京102206 [3]北京交通大学国家物理实验教学示范中心,北京100044

出　　处：《红外与激光工程》2024年第3期102-109,共8页Infrared and Laser Engineering

基　　金：国家自然科学基金项目(62105036,62105038,62005020);北京市教育委员会科学研究计划项目(KM202211232020,KM202211232001,KM202211232018)。

摘　　要：基于低维纳米材料的飞秒光纤激光器在光学开关、光纤传感和光通信领域中发挥着重要的作用。然而,低损伤阈值限制了其在高能量激光领域的实际应用。为了解决这一问题,实验中基于PbS量子点饱和吸收体,在近零色散区研究掺铒光纤激光器的飞秒脉冲输出特性,脉冲中心波长为1568.6 nm,光谱的3 dB带宽为11.4 nm,脉冲半高全宽为361 fs。利用多模光纤中的非线性多模干涉效应实现带宽可调的光谱滤波效应,调节偏振相关“基模”引起的群时间延迟量调控腔内总色散量,升高泵浦驱动电流达到饱和吸收体的反饱和吸收特性区域,实现从展宽脉冲到高能量耗散孤子共振脉冲的切换。由于局部的非同步色散波与孤子之间的相消干涉效应,导致耗散孤子共振脉冲光谱出现了dip型边带和Kelly边带不对称地分布在光谱两边的现象。通过调谐腔内脉冲的偏振状态和泵浦功率,高能量脉冲的半高全宽可以在7.7~23 ns之间调谐。当泵浦驱动电流达到800 mA时,腔内激光脉冲能量为34.8 nJ,其损伤阈值大于60 mJ/cm^(2)。该工作为实现高效、高能量飞秒光纤激光提供了新的解决方案。Objective With excellent photoelectric properties,low-dimensional nanomaterials show great promise for applications,such as optical switch,optical communication and industrial materials processing,particularly in combination with ultrashort pulse fiber laser.Passively mode-locking fiber laser is one of the important ways to generate ultrashort pulses.And carbon nanotube,graphene,black phosphorus and so on,have been used in lasing ultrashort pulses.However,low damage threshold is the fatal drawback of low dimensional nanomaterials,resulting in the inability to be applied to high-energy fiber lasers.Functional modified or customized nanomaterials have been studied in generating high-energy pulses.But these fiber lasers have mono-functional and no tunable features.Therefore,it is necessary to establish high-energy and flexible tunable fiber laser to meet the needs of different usage.For this purpose,a PbS quantum dots based passively mode-locking fiber is designed in this paper,where a piece of graded index multimode fiber is added to cavity,acting as a tunable filter and dispersion compensator.Methods A tunable high-energy passively mode-locking fiber laser is built in this paper.PbS quantum dots is chosen as the high-damage threshold saturable absorber.A 24 cm-long graded index with slightly stretching is performed to implement a tunable filter(Fig.1-2).Because of the principal modes in multi-mode fiber,the group delay resulting from them is in linear relationship with the length of multi-mode fiber.And they are polarization dependent.Therefore,the total cavity dispersion can be controlled by just adjusting the polarization states of fiber lasers,leading to the operation of cavity switchable.Results and Discussions By properly adjusting the polarization controller,a stretched pulsed fiber laser is established under the pump current of 245 mA(Fig.4).The center wavelength is located at 1568.6 nm,with 3 dB bandwidth of 11.4 nm,and the full width at half maximum(FWHM)is about 361 fs with a fundamental repetition frequ

关 键 词：PbS量子点 高能量脉冲 锁模光纤激光器 多模干涉效应 

分 类 号：TN248[电子电信—物理电子学]