Perfectly vertical surface grating couplers using subwavelength engineering for increased feature sizes Journal Articles uri icon

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  • 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 d B 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.


  • 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

publication date

  • July 1, 2020