Complementary metal–oxide–semiconductor compatible high efficiency subwavelength grating couplers for silicon integrated photonics
We demonstrate a through-etched grating coupler based on subwavelength nanostructure. The grating consists of arrays of 80 nm × 343 nm rectangular air holes, which can be patterned in a single lithography/etch. A peak coupling efficiency of 59% at 1551.6 nm and a 3 dB bandwidth of 60 nm are achieved utilizing the silicon-on-insulator platform with a 1 μm thick buried-oxide layer for transverse electric mode. The performance is comparable to gratings requiring much more complicated fabrication processes.
This research is supported by the AFOSR Small Business Technology Transfer (STTR) under Grant FA9550-11-C-0014 and the AFOSR Multi Disciplinary University Research Initiative (MURI), under Grant FA9550-08-1-0394, monitored by Dr. Gernot Pomrenke.
