Focusing-curved subwavelength grating couplers for ultra-broadband silicon photonics optical interfaces
Publication Type:Journal Article
Source:Optics Express, OSA, Volume 22, Number 15, p.18224--18231 (2014)
Keywords:Gratings; Subwavelength structures
We report on the design and characterization of focusing-curved subwavelength grating couplers for ultra-broadband silicon photonics optical interfaces. With implementation of waveguide dispersion engineered subwavelength structures, an ultra-wide 1-dB bandwidth of over 100 nm (largest reported to date) near 1550 nm is experimentally achieved for transverse-electric polarized light. By tapering the subwavelength structures, back reflection is effectively suppressed and grating coupling efficiency is increased to −4.7 dB. A compact device footprint of 40 µm x 20 µm is realized by curving the gratings in a focusing scheme.