垂直纳米光栅耦合器耦合效率分析与测试

摘要

We discuss the theory research and testing methods of a nano grating coupler based on SOI (Silicon-on Insulator). The grating coupling efficiency of parameters and the corresponding theoretical simulation was studied systematically, especially the dependence of the influence of grating etching with a duty cycle of 50%. Angles of the incident light were also researched. It is found that 10°of the incident light get the highest efficiency at 1 550 nm wavelength. Meanwhile,the coupling efficiency in theory can be improved to 76% using an optimized grating design and adding film which can effectively reduce the input light reflection and its leak scattering. The fabrication of the Si waveguide nano-grating coupler in Silicon -on-Insulator is focusing on ion beam method (FIB). Using single-mode NewFocus laser with an adjustable extent of 1 520 nm ~ 1 570 nm as the excitation optical source, a vertical coupler of Si waveguide grating is achieved through coupling to a single-mode fiber. The measured 1 dB bandwidth is ap proximately 30 nm and the maximum transmission measured is approximately 32%.%介绍了基于Sol纳米光栅耦合器的理论研究及测试方法,系统研究了光栅参数对光栅耦合效率的影响,在占空比为1:1的基础上,对不同光栅槽深作了相应的理论分析,同时,还对不同角度的入射光作了相应的研究,经过仿真在入射角为10°时,对于波长为l 550 nm的入射光其耦合效率最高.除此之外,通过在光栅表面添加增透膜使其耦合效率在理论上提高至76％以上,并实验验证了增透膜可以有效的降低输入光场的端面反射及波导表面散射,增强了输出光效率.采用聚焦离子束方法(FIB)在10 μm宽的硅波导上加工了纳米光栅结构,利用单模NewFocus可调谐激光器(1 520～1 570 nm)作为激发光源,对单模光纤与硅波导光栅进行垂直耦合,得到l dB带宽近似为30 nm,耦合效率约为32％.