中红外量子级联激光器1×16锁相阵列设计  

Design of 1×16 phase-locked array of quantum cascade laser in mid-infrared band

作　　者：王锐 张东亮 张程程 林青华 罗明馨 郑显通 祝连庆[1,2,3] Wang Rui;Zhang Dongliang;Zhang Chengcheng;Lin Qinghua;Luo Mingxin;Zheng Xiantong;Zhu Lianqing(Key Laboratory of Ministry of Education Optoelectronic Measurement Technology and Instrument,Beijing Information Science and Technology University,Beijing 100192,China;Instrumentation Science and Optoelectronic Engineering College,Beijing Information Science and Technology University,Beijing 100016,China;Guangzhou Nansha Intelligent Photonic Sensing Research Institute,Guangzhou 511462,China)

机构地区：[1]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,北京100192 [2]北京信息科技大学仪器科学与光电工程学院,北京100016 [3]广州南沙北科光子感知技术研究院,广东广州511462

出　　处：《红外与激光工程》2024年第5期46-56,共11页Infrared and Laser Engineering

基　　金：国家自然科学基金项目(62105039);北京学者计划研究项目(BJXZ2021-012-00046);北京市教育委员会科研计划项目(KM202111232019)。

摘　　要：针对中红外波段单管量子级联激光器存在输出功率有限的问题,提出相干阵列通过光放大后合束提升激光器功率的方法,研究波长为4.6μm的1×16量子级联激光器锁相阵列的结构设计与优化。通过设计低传输损耗、高光限制因子的单模波导确定器件各层材料外延厚度;通过设计由100%反射率和50%反射率的布拉格反射镜组成的种子激光器实现4.6μm单波长激光输出;通过设计由1×2多模干涉耦合器(MMI)和弯曲波导组成的1×16分束器实现低损耗均匀分束并锁相;通过设计输出端口的Al_(2)O_(3)增透膜厚度并利用电注入放大的方式实现激光器阵列的大功率输出。最终确定波导上GaInAs层厚度为0.25μm,下GaInAs层厚度为0.1μm,上包层InP厚度为3μm,下包层InP厚度为1μm。当单模波导宽度为5μm时,波导损耗为0.055 dB·cm^(-1),光限制因子为0.733。100%反射镜刻蚀深度为0.2μm,周期为728 nm,占空比为0.5,周期数为1000;50%反射镜刻蚀深度为0.2μm,周期为727 nm,占空比为0.1,周期数为690;当阵列间距为35μm时,分束器尺寸为3080μm×605μm,损耗为0.254 dB,其中MMI尺寸为19μm×126μm;出射端口采用0.7μm的Al_(2)O_(3)增透膜,透射率达到0.975。最后比较了不同放大器阵列间距的温度与远场分布,相关研究结论可为量子级联激光器锁相阵列的研制提供设计参考。Objective Quantum cascade laser(QCL)in the mid-infrared(MIR)band suffer from the problem of limited output power,and many important applications require high power outputs above the watt level and high beam quality.Simply increasing the width of the active region can obtain higher power output,but it often directly affects the beam quality and generates a large amount of heat in the core region that cannot be exported,resulting in the device not being able to operate continuously.If a set of narrow-ridge QCL phase-locked arrays,can greatly improve the thermal efficiency,but also avoid the different phases between the units QCL brought about by the problem of poor beam quality,to facilitate the realization of high-power continuous output.Methods The seed laser is designed with a resonator composed of a 50%Bragg mirror on the front and a 100%Bragg mirror on the back.A stable laser beam with a central wavelength of 4.6μm is achieved;a thermal simulation analysis was established to determine the array distance at the amplified end;in order to avoid the problem of poor beam quality caused by phase inconsistency between the laser array elements,the 1×16 beam splitter consisting of a multimode interference coupler(MMI)and a bend waveguide is designed,so that the seed optical passing through the beam splitter can maintain the phase consistency and realize the function of uniform beam splitting;Al_(2)O_(3)anti-reflection coating is plated on the array output port,and optical amplification is completed through the end amplification part to achieve coherent beam enhancement of laser output power.Results and Discussions The simulation results show that the reflectivity of the total and semi-reflector mirrors is 100%and 50%for the beam with a central wavelength of 4.6μm,indicating that optical with a wavelength of 4.6μm can be used to generate stable oscillations using the mirrors(Fig.8).The total transmittance of the 1×2 MMI output port with the taper is 99.8%,and the optical field distribution is clear and stable,indic

关 键 词：量子级联激光器 锁相阵列 分束 布拉格反射镜 多模干涉耦合器 

分 类 号：TN242[电子电信—物理电子学]