铌酸锂薄膜调制器的协同仿真与优化设计  

Collaborative Simulation and Optimal Design of LiNbO_(3) Thin Film Modulator

作　　者：杨登才[1] 陈雨康 王云新[2] 向美华 陈智宇 刘萍萍 兰天[1] YANG Dengcai;CHEN Yukang;WANG Yunxin;XIANG Meihua;CHEN Zhiyu;LIU Pingping;LAN Tian(Institute of Laser Engineering,Faculty of Materials and Manufacturing,Beijing University of Technology,Beijing 100124,China;College of Physics and Optoelectronics,Faculty of Science,Beijing University of Technology,Beijing 100124,China;Science and Technology on Electronic Information Control Laboratory,CETC29,Chengdu 610036,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]北京工业大学理学部物理与光电学院,北京100124 [3]中国电子科技集团第29研究所电子信息控制重点实验室,成都610036

出　　处：《北京工业大学学报》2021年第6期565-572,共8页Journal of Beijing University of Technology

基　　金：国家自然科学基金资助项目(61771438,61871007);装备预研基金资助项目(6141B08231102)。

摘　　要：电光调制器的半波电压和带宽主要取决于其电极结构,基于绝缘体上铌酸锂(lithium niobate on insulator, LNOI)结构调制器波导与基底折射率差为传统工艺的10倍左右,能够大幅提高光场和电场的重叠度,降低调制器的半波电压,提升调制带宽.当前迫切需要针对这一新型调制结构的电极进行优化设计.应用COMSOL Multiphysic和HFSS软件对LNOI结构的强度调制器进行协同仿真和优化设计.主要讨论了电极宽度、电极厚度、电极间距和上下包层厚度对调制器特性参数的影响,得到了调制器的电光重叠积分、微波折射率、微波衰减系数和电极特性阻抗等参数.在此基础上,通过约束算法优化设计这些性能参数达到提高带宽和降低半波电压的目的.结果表明,在电极长度为1 cm的情况下,半波电压约为2.17 V,3 dB带宽大于70 GHz.该研究工作对基于LNOI结构的电光调制器的电极设计具有重要的指导意义.The half-wave voltage and bandwidth of the electro-optic modulator depend mainly on its electrode structure.The difference of refractive index between the waveguide and the substrate of the modulator based on the lithium niobate on insulator(LNOI)is about ten times of the traditional technique,which can significantly improve the overlap degree of light field and electric field,reduce the half-wave voltage,and improve the bandwidth.Therefore,it is urgent to optimize the electrode design of this structure.In this paper,COMSOL Multiphysics and HFSS were used to simulate and optimize the electrode of intensity modulator based on LNOI structure.The effects of electrode width,electrode thickness,electrode gap,upper and lower cladding thickness on the characteristic parameters of the modulator were discussed.Then,the parameters of the modulator,such as electro-optic overlap integral,microwave effective refractive index,microwave attenuation coefficient and electrode characteristic impedance,were obtained.On this basis,these performance parameters were optimized to improve bandwidth and reduce half wave voltage.Results show that the half-wave voltage reaches 2.17 V,and the bandwidth of 3 dB is better than 70 GHz when the electrode length is 1 cm.The proposed work has important significance for the electrode design of LNOI-based electro-optic modulator.

关 键 词：协同仿真 薄膜铌酸锂 行波电极 相速匹配 重叠积分 电极结构参数 

分 类 号：TN252[电子电信—物理电子学]