▎ 摘　　要

We present theoretical and experimental results that demonstrate an increase in the grating bandwidth by placing a graphene on the chip. A focusing subwavelength grating with coupling efficiency of -4.3 dB and 1 dB bandwidth of similar to 60 nm was demonstrated. After a graphene sheet was transferred onto the chip, the maximum 1 dB bandwidth was increased to similar to 72 nm. Experimental results are consistent with the calculated graphene induced waveguide refractive index and dispersion changes, and the bandwidth improvement may be attributed to the reduction of grating dispersion. This study may be of interest for graphene-on-silicon photonic integrated circuit applications. (C) 2014 AIP Publishing LLC.