太赫兹量子级联激光器光频梳射频传输  

Radio Frequency Transmission in Terahertz Quantum Cascade Laser Frequency Combs

作　　者：刘涵 李子平 马旭红 吴澍民 廖小瑜 管玟 周康 赵逸然 曹俊诚[1,2] 黎华 LIU Han;LI Ziping;MA Xuhong;WU Shumin;LIAO Xiaoyu;GUAN Wen;ZHOU Kang;ZHAO Yiran;CAO Juncheng;LI Hua(Key Laboratory of Terahertz Solid State Technology,Shanghai Institute of Microsystem and Information Technology,Chinese Academy of Science,Shanghai 200050,China;Center of Materials Science and Optoelectronics Engineering,University of Chinese Academy of Science,Beijing 100049,China;School of Information Science and Technology,ShanghaiTech University,Shanghai 201210,China)

机构地区：[1]中国科学院上海微系统与信息技术研究所、中国科学院太赫兹固态技术重点实验室,上海200050 [2]中国科学院大学材料与光电研究中心,北京100049 [3]上海科技大学信息科学与技术学院,上海201210

出　　处：《光子学报》2023年第1期45-54,共10页Acta Photonica Sinica

基　　金：国家自然科学基金(Nos.61875220,61927813,62035005,61991430,62105351);中国科学院“从0到1”原始创新项目(No.ZDBS-LY-JSC009);国家优秀青年科学基金(No.62022084);上海市优秀学术带头人计划(No.20XD1424700);上海市青年拔尖人才开发计划。

摘　　要：针对太赫兹量子级联激光器光频梳射频信号提取与传输存在的阻抗不匹配问题,设计并提出了一种输入阻抗为20Ω、输出阻抗为50Ω的渐变微带线结构,研究了该结构的准TEM模电场分布,并根据S参数建立了相应的LC等效电路模型分析其物理机理。实验中,将渐变微带线结构应用于太赫兹量子级联激光器光频梳射频信号提取与测试,以验证渐变微带线传输射频信号效果,成功测量得到太赫兹量子级联激光器重复频率,其线宽为3.7 kHz,信噪比达到60 dB,在注入电流为700~900 mA范围内重复频率表现为稳定的单模信号,测量得到的最大保持和幅度艾伦方差结果同样表现出重复频率的稳定性。实验结果表明,所设计的渐变微带线具有良好的阻抗匹配效果,能够实现对太赫兹量子级联激光器光频梳射频信号稳定的提取和传输。The electrically pumped terahertz quantum cascade laser is characterized by high output power,low threshold,high quality far-field beam,etc.,which is one of the most efficient terahertz radiation sources in the frequency range between 1 THz and 5 THz.Due to its outstanding performances,the terahertz quantum cascade laser is an ideal semiconductor platform for the terahertz frequency comb generation.Different approaches,e.g.,group velocity dispersion engineering,active microwave injection locking,passive stabilization,etc.,have been employed to obtain broadband frequency combs based on terahertz quantum cascade lasers.Regardless of the stabilization technique employed,the radio frequency transmission in the terahertz quantum cascade laser cavity is a key point for the comb characterization,because the repetition frequency of the laser comb determined by the laser cavity length normally lies in the microwave frequency range.Previous studies mainly focus on the optimizations of laser structures to improve frequency stability.The design and optimization of broadband impedance matching unit are less investigated.In this article,a tapered microstrip line structure is designed to solve the impedance mismatching problem in the extraction and transmission of the radio frequency signal of the terahertz quantum cascade laser frequency comb.The input and output impedances of the tapered microstrip line structure are designed to be 20Ωand 50Ω,respectively.The simulation of the tapered microstrip line is carried out by employing a finite element method.The structure and parameter optimization of the tapered microstrip line is systematically studied.The calculated S_(21)and S_(11)are-0.1209 dB and-17.5133 dB,respectively,at the central frequency of 6.2 GHz.Then the electric field distribution of the tapered structure is simulated and the skin effect of the calculated electric field distribution of the tapered microstrip line is consistent with that of the traditional microstrip line.Furthermore,a corresponding equivalent circ

关 键 词：太赫兹 量子级联激光器 光频梳 阻抗匹配 渐变微带线 

分 类 号：TN248.4[电子电信—物理电子学]