有源光纤中稀土离子激光上能级寿命测量的研究  

Upper-laser-level lifetime measurement of rear earth dopant in active fiber

作　　者：刘恒 张钧翔 付士杰 盛泉[1,2] 史伟[1,2] 姚建铨[1,2] Liu Heng;Zhang Jun-Xiang;Fu Shi-Jie;Sheng Quan;Shi Wei;Yao Jian-Quan(Institute of Laser and Optoelectronics,Tianjin University,Tianjin 300072,China;Key Laboratory of Optoelectronic Information Science and Technology(Ministry of Education),Tianjin University,Tianjin 300072,China;College of Optical Science,University of Arizona,Arizona 85721,USA)

机构地区：[1]天津大学精密仪器与光电子工程学院,天津300072 [2]天津大学,光电信息技术教育部重点实验室,天津300072 [3]亚利桑那大学光学科学学院,亚利桑那85721

出　　处：《物理学报》2019年第22期294-301,共8页Acta Physica Sinica

基　　金：国家重点研发计划(批准号:2017 YFF0104603);高等学校学科创新引智计划(批准号:B17031)资助的课题~~

摘　　要：提出了一种基于脉冲光纤激光放大器能量特性测量有源光纤中稀土离子上能级寿命的方法.根据光纤激光器速率方程,能够确定有源光纤中反转粒子数储能随抽运功率和时间的变化关系;实验测量不同种子光脉冲重复频率下放大器输出单脉冲能量的变化,可以反映出反转粒子数随时间的变化情况,进而根据理论模型得到激活离子的激光上能级寿命.实验搭建了1.06μm掺镱(Yb^3+)光纤激光放大系统对该测量方法理论模型的合理性进行了验证,对几种常见商用掺Yb^3+有源光纤激光上能级寿命分别进行了多次测量和数据处理,测量结果以及变化趋势与其他相关报道中的结果相符.The upper-laser-level lifetime(fluorescence lifetime)of the rear earth dopant in the active fiber is a key parameter which indicates the performance of the fiber,and takes an important role in designing the laser system.However,the accurate measurement of fluorescence lifetime in active fiber remains challenging,which mainly rely on the direct measurement of laser induced fluorescence lifetime of the active fiber or lifetime measurement of bulk laser glass.The former method suffers the error due to the amplified spontaneous emission and the reabsorption process,while the latter ignores the influence of high temperature and tension produced during the fiber drawing on the emission behavior of the material.Therefore,the accuracy of these measurements can become a problem.In this work,we propose a new approach to measuring the upper-laserlevel lifetime of the rear earth dopant in the active fiber based on the power/energy performance of the fiber amplifier.The population inversion,i.e.the energy storage,in the active fiber of a fiber amplifier is a function of upper-laser-level lifetime.Therefore,the upper-laser-level lifetime can be derived by measuring the average power or output pulse energy of the amplifier,given that the energy storage in the active fiber is extracted adequately by a seed laser.Using the rate equations,we model the population inversion and energy storage in the active fiber each as a function of pump power and time,and the resulting relationship between the upperlaser-level lifetime and the average output power.The upper-laser-level lifetimes of several commercial Ybdoped active fibers are experimentally measured by this method through using the fibers as the gain media of the amplifier operated at 1064 nm.The convenience of experimental data processing is also discussed.The measured lifetime and evolution trend of the lifetime with dopant concentration exhibitthat they are in good agreement with those from other reports and the theoretical model,which verifies the feasibility of this method.

关 键 词：上能级寿命 有源光纤 光纤激光器 光纤放大器 

分 类 号：TN2[电子电信—物理电子学]