基于Bragg光栅的超高消光比SOI波导偏振器设计  

Design of Bragg grating-based ultra-high extinction ratio polarizer on silicon-on-insulator waveguide

作　　者：毛玉政 陈亚婧 朱京平[2] Mao Yuzheng;Chen Yajing;Zhu Jingping(Xi’an Flight Automatic Control Research Institute,Aviation Industry Corporation of China,Xi’an 710065,China;School of Electronic Science and Engineering,Xi’an Jiaotong University,Xi’an 710049,China)

机构地区：[1]航空工业西安飞行自动控制研究所,陕西西安710065 [2]西安交通大学电子科学与工程学院,陕西西安710049

出　　处：《红外与激光工程》2022年第8期392-398,共7页Infrared and Laser Engineering

摘　　要：波导偏振器是片上集成相干光学系统中的关键器件之一,超高消光比、低损耗、紧凑型波导偏振器的设计一直是研究的热点。基于绝缘体上硅平台的倾斜Bragg光栅被用于实现超高消光比波导偏振器结构。利用一维光子晶体能带理论分别计算TE和TM模式光的能带结构分布,选择TE模式禁带与TM导带重叠带隙设计光栅,可实现TM模式低损传输,而TE模式被Bragg光栅高效反射,从而产生超高偏振消光比。3D FDTD仿真表明:16μm倾斜Bragg光栅波导偏振器可在中心波长1550 nm附近70 nm的带宽内,实现大于37 dB的超高消光比,器件的损耗小于0.64 dB;进一步增加光栅周期数,当长度为25μm时,消光比可提高至46 dB。Bragg光栅倾斜角与刻蚀宽度偏差仿真表明:设计的结构加工误差容限较大,同时该结构仅需一次曝光刻蚀,工艺流程简单。The waveguide polarizer is a key component of an on-chip integrated coherent optical system,and it has attracted much interest to design a waveguide polarizer with an ultrahigh extinction ratio,low excess loss and compact size in photonic integrated circuits.A tilted Bragg grating-based polarizer on a silicon-on-insulator platform was proposed and designed by one-dimensional photonic crystal band gap theory.The energy band structure distribution for the TE and the TM modes were calculated using the energy band theory of onedimensional photonic crystals,and the overlap gap between the forbidden band of theTE mode and the transmission band of the TM mode were used to determine the grating structure parameters.As a result,the TM mode light could pass through the Bragg grating waveguide with a low excess loss,while the TE mode shows almost complete reflection,introducing an extremely high polarization extinction ratio.The 3D FDTD simulation results suggest that a 16μm titled Bragg grating-based waveguide polarizer could achieve an ultrahigh extinction ratio of more than 37 dB at the central wavelength of 1550 nm over a broad bandwidth of 70 nm,and the excess loss of the device is less than 0.64 dB.With an increasing length of waveguide to 25μm,the extinction ratio could further reach up to 46 dB.The effects of the tilt angle and etching deviation on the performance of the polarizer were also studied,and the results show that the designed structure has a good fabrication tolerance.In addition,the polarizer only needs one-step etching with a simple fabrication process.

关 键 词：偏振器 BRAGG光栅 一维光子晶体 SOI波导 

分 类 号：TN256[电子电信—物理电子学]