氮化硅片上光栅耦合器的优化和实验  

Optimization and Experiments of On-Chip Silicon Nitride Grating Couplers

作　　者：冉娜 陈昕阳 汪正坤 张洁[1] Ran Na;Chen Xinyang;Wang Zhengkun;Zhang Jie(Key Laboratory of Optoelectronic Technology&Systems,Ministry of Education,Chongqing University,Chongqing 400044,China)

机构地区：[1]重庆大学光电技术及系统教育部重点实验室,重庆400044

出　　处：《光学学报》2023年第1期150-157,共8页Acta Optica Sinica

基　　金：国家自然科学基金(62175023,61875024);重庆市杰出青年基金(cstc2019jcyjjqX0018)。

摘　　要：在785 nm激励的拉曼片上传感器结构中,氮化硅片上光栅耦合器的性能直接关系到激励光的耦合效果。首先建立了光栅耦合器的二维、三维结构模型,采用时域有限差分(FDTD)仿真软件对光栅耦合器进行数值分析。以耦合效率为主要性能指标,分析了光源入射角度、光栅常数、光栅高度、填充因子和光栅刻蚀深度各参数的影响。采用电子束光刻法制备了光栅耦合器。最后,对三维全刻蚀聚焦波导光栅耦合器进行了测试。结果表明,二维波导光栅耦合器的性能最好,其耦合效率可达39.64%,三维全刻蚀聚焦波导光栅耦合器在实际测试中的耦合效率能达19.91%。光栅耦合器能有效将光耦合进波导中,在波导传感中具有潜在的应用。Objective The integration of Raman spectroscopy detection system is the current focus of Raman technology, especially combining waveguide with Raman, and effectively coupling excitation light into waveguide is particularly important for Raman spectroscopy sensing and signal collection. The process is mainly realized by waveguide grating couplers.However, the majority of the waveguide grating couplers are studied for the C band. In addition, the physical designs of the grating couplers are very complex and the preparation processes are difficult. The transparent window of the silicon nitride used in this paper is between 400 nm and 3500 nm. It has a wide range and a high refractive index, which can form a refractive index difference with the surrounding materials to bind the energy of the light in the waveguide layer, and it can reduce the transmission loss of light in the waveguide. The grating coupler designed here has a simple structure and preparation process. Besides, the wavelength of excitation light is 785 nm, which is also commonly used in Raman sensing. The grating couplers studied here can effectively couple the excitation light into the waveguide, and it is helpful for Raman spectroscopy sensing and signal collection.Methods Firstly, we have a theoretical analysis based on the principle of the grating coupler and analyze the interaction of parameters and the effect of each parameter on the coupling efficiency. Then the two-dimensional and three-dimensional models of the grating couplers are established, and the finite difference time domain(FDTD) simulation software is used to analyze them. With coupling efficiency as the main performance index, the influences of incident angle, grating constant,grating height, filling factor, and etching depth are analyzed to achieve the maximum of the coupling efficiency of the grating couplers. Electron beam lithography is used to prepare three-dimensional fully etched and focused waveguide grating couplers and an optical system including a supercontinuum source, tu

关 键 词：集成光学 光栅耦合器 氮化硅波导 结构优化 耦合效率 

分 类 号：TN26[电子电信—物理电子学]