Kamandar Dezfouli Mohsen, Grinberg Yuri, Melati Daniele, Cheben Pavel, Schmid Jens H, Sánchez-Postigo Alejandro, Ortega-Moñux Alejandro, Wangüemert-Pérez Gonzalo, Cheriton Ross, Janz Siegfried, Xu Dan-Xia
Opt Lett. 2020 Jul 1;45(13):3701-3704. doi: 10.1364/OL.395292.
We present perfectly vertical grating couplers for the 220 nm silicon-on-insulator platform incorporating subwavelength metamaterials to increase the minimum feature sizes and achieve broadband low back-reflection. Our study reveals that devices with high coupling efficiencies are distributed over a wide region of the design space with varied back-reflections, while still maintaining minimum feature sizes larger than 100 nm and even 130 nm. Using 3D-finite-difference time-domain simulations, we demonstrate devices with broadband low back-reflection of less than -20 over more than 100 nm bandwidth centered around the C-band. Coupling efficiencies of 72% and 67% are achieved for minimum feature sizes of 106 nm and 130 nm, respectively. These gratings are also more fabrication tolerant compared to similar designs not using metamaterials.
我们展示了用于220纳米绝缘体上硅平台的完美垂直光栅耦合器，其集成了亚波长超材料以增加最小特征尺寸并实现宽带低背反射。我们的研究表明，具有高耦合效率的器件分布在设计空间的广泛区域内，背反射各不相同，同时仍保持大于100纳米甚至130纳米的最小特征尺寸。通过三维时域有限差分模拟，我们展示了在以C波段为中心的超过100纳米带宽上具有小于-20的宽带低背反射的器件。对于最小特征尺寸分别为106纳米和130纳米的情况，耦合效率分别达到了72%和67%。与未使用超材料的类似设计相比，这些光栅对制造工艺的容忍度也更高。
