Graphene based low insertion loss electro-absorption modulator on SOI waveguide

Graphene is considered a promising material for broadband opto-electronics because of its linear and gapless band structure. Its optical conductivity can be significantly tuned electrostatically by shifting the Fermi level. Using mentioned property, we experimentally demonstrate a graphene based electro-absorption modulator with very low insertion loss. The device is realized on a silicon on insulator (SOI) waveguide operating at 1550 nm wavelength. The modulator shows a modulation depth of 16 dB and an insertion loss of 3.3 dB, surpassing GeSi and previous graphene based absorption modulators and being comparable to silicon Mach-Zehnder interferometer based modulators.