Compact microring resonator based on ultralow-loss multimode silicon nitride waveguide  

作　　者：Shuai Cui Kaixiang Cao Zhao Pan Xiaoyan Gao Yuan Yu Xinliang Zhang 

机构地区：[1]aHuazhong University of Science and Technology,School of Optical and Electronic Information,Wuhan National Laboratory for Optoelectronics,Wuhan,China [2]Optics Valley Laboratory,Wuhan,China

出　　处：《Advanced Photonics Nexus》2023年第4期88-95,共8页先进光子学通讯（英文）

基　　金：supported by the National Natural Science Foundation of China(Grant No.61975249);the National Key Research and Development Program of China(Grant No.2018YFA0704403);the Program for HUST Academic Frontier Youth Team(Grant No.2018QYTD08).

摘　　要：Silicon nitride(Si3N4)waveguides with high confinement and low loss have been widely used in integrated nonlinear photonics.Indeed,state-of-the-art ultralow-loss Si3N4 waveguides are all fabricated using complex fabrication processes,and all of those reported that high Q microring resonators(MRRs)are fabricated in laboratories.We propose and demonstrate an ultralow-loss Si3N4 racetrack MRR by shaping the mode using a uniform multimode structure to reduce its overlap with the waveguide.The MRR is fabricated by the standard multi project wafer(MPW)foundry process.It consists of two multimode straight waveguides(MSWs)connected by two multimode waveguide bends(MWBs).In particular,the MWBs are based on modified Euler bends,and an MSW directional coupler is used to avoid higher-order mode excitation.In this way,although a multimode waveguide is used in the MRR,only the fundamental mode is excited and transmitted with ultralow loss.Meanwhile,thanks to the 180 deg Euler bend,a compact chip footprint of 2.226 mm perimeter with an effective radius as small as 195μm and a waveguide width of 3μm is achieved.Results show that based on the widely used MPW process,a propagation loss of only 3.3 dB∕m and a mean intrinsic Q of around 10.8 million are achieved for the first time.

关 键 词：silicon nitride microring resonator ultrahigh-Q factor 

分 类 号：TN2[电子电信—物理电子学]