Double‐layer graphene on photonic crystal waveguide electro‐absorption modulator with 12 GHz bandwidth

Graphene has been widely used in silicon‐based optical modulators for its ultra‐broadband light absorption and ultrafast optoelectronic response. By incorporating graphene and slow‐light silicon photonic crystal waveguide (PhCW), here we propose and experimentally demonstrate a unique double‐layer graphene electro‐absorption modulator in telecommunication applications. The modulator exhibits a modulation depth of 0.5 dB/μm with a bandwidth of 13.6 GHz, while graphene coverage length is only 1.2 μm in simulations. We also fabricated the graphene modulator on silicon platform, and the device achieved a modulation bandwidth at 12 GHz. The proposed graphene‐PhCW modulator may have potentials in the applications of on‐chip interconnections.