基于嵌入填充层的薄膜铌酸锂-氮化硅电光调制器  

Thin-Film Lithium Niobate-Silicon Nitride Electro-Optic Modulator Based on Embedded Filling Layer

作　　者：沈祥国 徐银 董越 张博 倪屹[1,2] Shen Xiangguo;Xu Yin;Dong Yue;Zhang Bo;Ni Yi(School of Internet of Things Engineering,Jiangnan University,Wuxi 214122,Jiangsu,China;Institute of Advanced Technology,Jiangnan University,Wuxi 214122,Jiangsu,China)

机构地区：[1]江南大学物联网工程学院,江苏无锡214122 [2]江南大学先进技术研究院,江苏无锡214122

出　　处：《光学学报》2023年第14期140-149,共10页Acta Optica Sinica

基　　金：国家自然科学基金(62205129);江苏省自然科学基金(BK20200592);中央高校基本科研基金(JUSRP12024)。

摘　　要：提出一种异质集成型薄膜铌酸锂电光调制器,由底部氮化硅波导、中间BCB黏合层、顶部铌酸锂薄膜构成调制区波导结构,调制电极位于铌酸锂薄膜的上部且二者之间填充了低折射率的SiO2,以利于实现折射率匹配并降低光损耗、微波损耗。进一步利用马赫-曾德尔干涉仪结构,设计了相应的电光调制器,并提出一种倒台阶型薄膜结构,该结构可实现输入、输出波导与调制区波导的高效耦合。对该电光调制器进行行波高速匹配设计,所得器件的半波电压长度积为1.77 V·cm,3 dB调制带宽为140 GHz,且调制区长度仅为5 mm。所提器件结构有望在大带宽薄膜铌酸锂电光调制器设计中发挥优势,助力薄膜铌酸锂光子集成器件的快速发展。Objective With the progress of optical communication technology,optoelectronic devices are developing toward low power consumption,large data bandwidth,and high integration.The electrooptic modulator(EOM),a key optoelectronic device,plays a vital role in connecting the electric and optical fields,where the onchip integration,high efficiency,low power consumption,and large bandwidth are always the crucial development directions of EOMs.Up to now,lithium niobate(LN)is still one of the most ideal materials for electrooptic modulation due to its excellent properties of wide transparent windows,strong Pockels effect,as well as stable physical and chemical features.However,the currently used EOMs are based on the bulk LN material,and the key modulation waveguides are formed by titanium diffusion or proton exchange on the bulk LN.Therefore,the formed waveguides have a low refractive index contrast(∆n≈0.02),which leads to a large waveguide size required to well confine the optical mode,and the EOM footprint is also relatively large inevitably.Recently,the thinfilm lithium niobate(TFLN)wafer has been fabricated by the smart cutting process and made available by several commercial companies.The TFLN wafer not only inherits some excellent material properties of LN but also has a high refractive index contrast(∆n≈0.8),a feature considerably beneficial for shrinking the device footprint and making the onchip compact integration available.In general,the TFLNbased EOMs can be divided into two types.One performs etching on the TFLN wafer to form the required waveguide,and the other deposits other high refractive index materials atop or below the TFLN wafer to form the waveguide,where the TFLN wafer does not need to be etched.By comparison,the etchingfree TFLN scheme can reduce the fabrication difficulty.Therefore,we focus on the etchingfree TFLN structure and propose a heterogeneously integrated EOM using embedded filling layers.Methods The structure of the proposed device is divided into three parts:the structural desig

关 键 词：集成光学 集成光器件 调制器 铌酸锂 集成光学材料 

分 类 号：TN252[电子电信—物理电子学]