高效率多通泵浦平面波导激光放大器  

High Efficiency Multipass Pumped Planar Waveguide Laser Amplifier

作　　者：曲波[1] 刘奇[1] 王思博 李强[1,2,3,4] Qu Bo;Liu Qi;Wang Sibo;Li Qiang(Institute of Laser Engineering,Faculty of Materials and Manufacturing,Beijing University of Technology,Beijing 100124,China;Beijing Engineering Research Center of Laser Technology,Beijing 100124,China;Beijing Colleges and Universities Engineering Research Center of Advanced Laser Manufacturing,Beijing 100124,China;Key Laboratory of Trans-Scale Laser Manufacturing Technology,Ministry of Education,Beijing 100124,China)

机构地区：[1]北京工业大学材料与制造学部激光工程研究院,北京100124 [2]北京市激光应用技术工程技术研究中心,北京100124 [3]激光先进制造北京市高等学校工程研究中心,北京100124 [4]跨尺度激光成型制造技术教育部重点实验室,北京100124

出　　处：《中国激光》2021年第16期8-21,共14页Chinese Journal of Lasers

基　　金：国家自然科学基金(62075003);北京市自然科学基金(4202007,KZ202110005010)。

摘　　要：设计了一种高效率、结构紧凑的高功率平面波导激光放大器。放大器使用新型平面波导结构,可以实现对芯层的多通泵浦,从而大幅度增加泵浦光的吸收长度,提高低掺杂Yb∶YAG芯层的泵浦吸收率。基于Yb3+的激光动力学方程,结合光学追迹法与有限元方法构建了三维激光放大模型,并分别对双包层平面波导与新型平面波导的高功率激光放大器进行仿真。仿真结果表明,当泵浦总功率为10 kW和注入种子光的功率为200 W时,新型平面波导放大器具有更高的泵浦吸收率、更好的泵浦均匀性、更低的热损伤风险及更高的光-光转化效率。Objective Planar waveguide amplifiers have the advantages of slab and fiber ones and become an essential branch of the high average power solid-state lasers.Yd∶YAG planar waveguide amplifiers have the potential for higher output than Nd∶YAG due to the less generated heat and higher extraction efficiency under the same absorption pump power.The absorption cross-section of Yd∶YAG is smaller than Nd∶YAG;a higher doping concentration of the core and end-pumping must fully absorb the pump power.To maximize extraction efficiency,the doping concentration is significantly reduced due to self-absorption.To ensure that the pump power can be fully absorbed,extending the length of the core is necessary.However,the size of the core is limited by the process conditions.If the doping concentration is sufficiently small,the end-pumping cannot meet the absorption of pump power requirements.In this study,we design a multipass pumped planar waveguide with the low-doped Yd∶YAG core to prolong the pump absorption length.The amplifier using a multipass pumped planar waveguide shows higher pump absorption,better absorption uniformity,and higher optical-optical efficiency than the double-clad planar waveguide amplifier.We hope that the new structure can provide methods and ideas for designing and optimizing planar waveguide lasers.Methods Based on the theory of single-mode transmission and laser mode competition in the planar waveguide,the core and inner cladding of the planar waveguide are Yb∶YAG with a thickness of 0.2 mm and a doping concentration of 1%and Er∶YAG with a thickness of 0.5 mm and a doping concentration of 0.5%,respectively.The core and inner-claddings form the core area,which is 80.0 mm×16.0 mm×1.6 mm.YAG is bonded around the core area with a thickness of 1.2 mm.The outer-claddings of 1 mm cover the core and expansion areas,forming a double-cladding waveguide with the core area and a single-cladding waveguide with the expansion area.A multipass pumping ray path in the waveguide is formed through internal

关 键 词：激光器 低掺杂Yb∶YAG 平面波导 激光放大器 高效率 多通泵浦 

分 类 号：TN248.1[电子电信—物理电子学]