Wideband switch enhanced by photonic crystal waveguide with graphene nanosheet heater

A compact wideband optical switch assisted by graphene nanosheet heater is demonstrated by shifting the bandedge of the photonic crystal waveguides (PhCWG) through current-induced heating. The high heating efficiency of graphene and the high light-matter interactions in slow-light PhCWG are combined to enhance the heating efficiency and extinction ratio. The extinction ratio is increased from 15 dB to 22 dB and the tuning bandwidth is up to 20 nm with only 28 K temperature change. Our measurements match well with simulation results, suggesting an effective way for CMOS compatible chip-scale integrated graphene microheater switch.