Design of a high-speed electro-absorption modulator based on graphene and microfiber

A high-speed traveling wave electro-absorption modulator based on grapheme-micro fiber is designed. Graphene modulates the optical transmission intensity by changing its fermi level under different applied voltages. Graphene has an extremely high carrier mobility which has a potential electrical bandwidth of 500 GHz. However, the bandwidth of the state-of-art graphene based modulator is limited by the RC constants rather than the carrier transit time. Here we apply the traveling wave electrodes to improve the bandwidth of the graphene-microfiber modulator. The coplanar strip electrodes are designed to match the group velocity of the microwave and optical signal. We also target to reduce the RF loss and realize the impedance matching. We have designed a graphene-microfiber electro-absorption modulator with 15dB extinction ratio and 62GHz electrical bandwidth.