飞秒脉冲抽运掺镱微结构光纤产生超连续谱的实验研究  

Experimental study of supercontinuum generation in Yb3+-doped microstructure fiber pumped by femtosecond pulses

作　　者：王伟[1,2,3] 左玉婷 董婷婷[1,2] 朱维震[1,2] 林天旭 徐海东 卿源 韩颖 齐跃峰 侯蓝田 Wang Wei;Zuo Yu -Ting;Dong Ting -Ting;Zhu Wei -Zhen;Lin Tian -Xu;Xu Hai -Dong;Qing Yuan;Han Ying;Qi Yue -Feng;Hou Lan -Tian(School of Information Science and Engineering,Yanshan University,Qinhuangdao 066004,China;Key Laboratory for Special Fiber and Fiber Sensor of Hebei Province,Qinhuangdao 066004,China;Jiangsu Key Laboratory of Meteorological Observation and Information Processing,Nanjing University of Information Science and Technology,Nanjing 210044,China)

机构地区：[1]燕山大学信息科学与工程学院,秦皇岛066004 [2]河北省特种光纤与光纤传感重点实验室,秦皇岛066004 [3]南京信息工程大学,江苏省气象探测与信息处理重点实验室,南京210044

出　　处：《物理学报》2019年第13期156-164,共9页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:61405173,61735011);河北省自然科学基金(批准号:F2016203389);江苏省气象探测与信息处理重点实验室(批准号:KDXS1107)资助的课题~~

摘　　要：本文利用钛蓝宝石飞秒激光器抽运自制的掺镱微结构光纤,对微结构光纤中的非线性效应及超连续谱产生机理进行了实验研究.研究发现,当抽运光偏离Yb^3+吸收最高峰85 nm时,仍具有较高的发光效率.在飞秒脉冲抽运下,位于反常色散区的发射光首先被位于正常色散区的抽运光激发、放大并俘获,然后演化为超短脉冲,随后在微结构光纤中产生非线性效应.微结构光纤1发射光位于零色散波长附近,产生基阶孤子并在拉曼作用下红移,微结构光纤2发射光位于距离零色散波长较远的反常色散区,产生高阶孤子分裂效应形成超连续谱,但是1380 nm处的OH-吸收限制了超连续谱的进一步展宽.忽略抽运光耦合效率、微结构光纤损耗等因素的影响,输出光谱中超连续谱的产生效率最高可以达到98%以上,意味着几乎所有的残余抽运光和发射光均展宽为超连续谱.在0.50 m长的微结构光纤中,获得了较高的波长转换效率和较宽的超连续谱.通过拉锥处理,零色散波长发生蓝移,最终产生的超连续谱相在短波处范围展宽,而在长波处范围缩短.因此利用钛蓝宝石飞秒激光器抽运Yb^3+掺杂微结构光纤,可以获得可调谐的超连续谱.The nonlinear effects and supercontinuum generation by the concept of wavelength conversion and amplification are experimentally studied in two Yb^3+-doped microstructure fibers(Yb^3+-MSFs),with the Ti:sapphire femtosecond pulses used as pump.Firstly,two Yb^3+-MSFs are pumped by continuous wave separately to obtain the emission spectrum.The relationship between the luminous efficiency and the deviation of pump light from the Yb^3+absorption peak is studied for each of the two fibers.The experimental results indicate that the luminous efficiency decreases as the deviation increases.However,both fibers still have high luminous efficiency even when the deviation reaches to 85 nm.Secondly,the supercontinuum spectrum is generated by the femtosecond laser pumping the cores of the two fibers.The influence of the pump power,relative position between emission light and zero-dispersion wavelength l0,pump wavelength and fiber length on the supercontinuum generation are studied.The results demonstrate that the amplified emission light at 1035 nm is first captured by the pump light to evolve into ultrashort pulse,and nonlinear effects are subsequently generated.As the pump power increases,for Yb^3+-MSF1 whose l0 is located near the emission light of Yb^3+irons,the fundamental soliton is generated and further shifts toward red region under Raman effect.Compared with Yb^3+-MSF1,the Yb^3+-MSF2 has a small core,which means that its l0 is short and the emission light is located in its anomalous dispersion region far from the l0.Experimental results reveal that higher-order soliton and soliton fission are more likely to happen and supercontinuum spectrum can be formed.However,the further broadening of the supercontinuum spectrum is limited by OH^-absorption at 1380 nm.Either increasing the deviation of pump light from the Yb^3+absorption peak or shortening the fiber length reduces the accumulated power of the emission light,so the experimental results show that red-shift of Raman soliton is reduced and the supercontinuum spectrum i

关 键 词：掺镱微结构光纤 超连续谱产生 波长转换 

分 类 号：TN253[电子电信—物理电子学] TN248.1