Hung Yung-Jr, Li Zhong-Ying, Chung Hung-Ching, Liang Fu-Chieh, Jung Ming-Yang, Yen Tzu-Hsiang, Tseng Shuo-Yen
Opt Lett. 2019 Feb 15;44(4):815-818. doi: 10.1364/OL.44.000815.
We report a 2×2 broadband and fabrication tolerant mode-evolution-based 3 dB coupler based on silicon-on-insulator rib waveguides. The operating principle of the coupler is based on the adiabatic evolution of local eigenmodes. The key element of the device is an adiabatically tapered mode evolution region, which converts two dissimilar waveguides into two identical waveguides. Contrary to conventional designs using a linear taper function where the device adiabaticity is uneven during evolution, we use the fast quasiadiabatic approach to homogenize the adiabaticity of the device, leading to a shortcut to adiabaticity. Devices with an optimized taper region of 26.3 μm are designed and fabricated in a complementary metal-oxide-semiconductor compatible process with 193 nm deep ultraviolet lithography. The measured devices exhibit a broadband 3 dB±0.5 dB splitting within a bandwidth of 100 nm, uniformly across a 200-mm wafer, showing good tolerance against fabrication variations.
我们报道了一种基于绝缘体上硅肋形波导的2×2宽带且对制造工艺宽容的基于模式演化的3分贝耦合器。该耦合器的工作原理基于局部本征模式的绝热演化。该器件的关键元件是一个绝热渐变的模式演化区域，它将两个不同的波导转换为两个相同的波导。与使用线性渐变函数的传统设计不同，在传统设计中器件的绝热性在演化过程中不均匀，我们采用快速准绝热方法来使器件的绝热性均匀化，从而实现绝热捷径。具有26.3μm优化渐变区域的器件采用193nm深紫外光刻技术在互补金属氧化物半导体兼容工艺中进行设计和制造。所测量的器件在100nm带宽内呈现出宽带3分贝±0.5分贝的分光特性，在200mm晶圆上均匀分布，显示出对制造工艺变化的良好耐受性。
