Low-Loss On-Chip Surface Grating Couplers Engineered Using Subwavelength-Structured Metamaterials

The presence of low-loss optical interfaces is arguably one of the key factors to succeed for silicon photonics. Here, we report on our latest advances in subwavelength-structured and metamaterial-engineered fiber-chip grating couplers with a L-shaped waveguide profiles. Grating couplers are made in silicon-on-insulator platform and facilitate robust sub-decibel coupling of light with device features lying well in the range of available fabrication technologies.