薄膜铌酸锂多尖端端面耦合结构  

Multi-Tip Edge Coupler of Thin-Film Lithium Niobate Chip

作　　者：王嘉毅 蔡明璐 李天怡 张栩嘉 陈建平[1] 吴侃 Wang Jiayi;Cai Minglu;Li Tianyi;Zhang Xujia;Chen Jianping;Wu Kan(State Key Laboratory of Advanced Optical Communication Systems and Networks,Shanghai Institute for Advanced Communication and Data Science,School of Electronic Information and Electrical Engineering,Shanghai Jiao Tong University,Shanghai 200240,China)

机构地区：[1]上海交通大学电子信息与电气工程学院,上海先进通信与数据科学研究院,区域光纤通信网与新型光通信系统国家重点实验室,上海200240

出　　处：《光学学报》2024年第11期115-122,共8页Acta Optica Sinica

基　　金：国家自然科学基金(61922056)。

摘　　要：为提升薄膜铌酸锂芯片端面耦合的效率和稳定性,结合铌酸锂材料的刻蚀特点和工艺条件,设计并研究双层多尖端逆锥形的耦合结构。通过仿真计算、参数扫描和对比分析,探究双尖端和三尖端逆锥形耦合结构的特性及其参数选取方案。多尖端设计可扩大端面处的模场,从而降低对加工精度的要求。在侧壁倾角62°和最小宽度150 nm的工艺条件下,理想的双尖端和三尖端结构分别在1550 nm波长处实现0.47 dB和1.04 dB的单端耦合损耗,且具有较大的工作带宽和对准容差。最后,结合多尖端耦合结构的制造和测试结果,分析薄膜铌酸锂芯片上端面耦合结构的优化方案,为进一步实现低损耗耦合结构奠定基础。Objective With the increasing amount of information in today’s world,optical signal transmission and correlation devices are becoming increasingly important.Photonic chips miniaturize and integrate various photonic devices with the advantages of low cost and low power consumption.When a photonic chip works,it must couple the optical signal between the chip and the outside fiber.The edge coupling scheme has the benefits of a large working bandwidth and low packaging difficulty,which makes batch manufacturing easy,and has promising application prospects.In the edge coupling process,the size difference between the fiber and the waveguide leads to a large mode field mismatch between them,which is the main factor of the coupling loss.The coupling structure designed on the chip to expand the spot can effectively improve mode overlap.Many schemes have been proposed and implemented on the silicon-on-insulator(SOI)platform,such as three-dimensional amplification waveguides,inverse taper designs,and subwavelength gratings.Lithium niobate is an excellent material for manufacturing optical devices that exhibits outstanding electro-optic,acousto-optic,and nonlinear properties.The lithium niobate on insulator(LNOI)platform is also an ideal solution for optoelectronic chip integration systems.The edge coupling structure of lithium niobate thin-film chips mostly adopts layered etching and an inverse taper structure to guide spot diffusion into the cladding,thereby improving the mode overlap.However,owing to the difficulty in processing lithium niobate,there is still room for improvement in this research area.To improve the efficiency and stability of the edge coupler on thin-film lithium niobate chips,this study designed and studied a double-layer multi-tip inverse taper structure based on the etching process conditions.Methods In this study,the characteristics and parameter selection schemes of double-and triple-tip inverse taper structures were explored using simulation calculations,parameter sweeping,and comparative analysi

关 键 词：集成光学 端面耦合 逆锥形结构 薄膜铌酸锂 光子集成 

分 类 号：O436[机械工程—光学工程]