Atto-joule energy-efficient graphene modulator using asymmetric plasmonic slot waveguide

Abstract

In this work, we propose a graphene-based electro-absorption modulator design using an asymmetric plasmonic slot waveguide. Such asymmetric slot waveguide allows us to achieve a strong light-matter interaction with a large orientation match between the polarization of confined modal field and graphene plane. Thus, a significant change in total optical absorption and, hence, modulation efficiency is achieved over a small active interaction length. The modulation efficiency is further enhanced by employing double-layer graphene and using both of them as tunable absorber. Reduced interaction length also lowers the device capacitance, which allows realizing compact devices with switching energy as low as 86.45 aJ/bit and modulation bandwidth over 1 THz for a 3 dB device length of 1.6 μm at an operating wavelength of 1550 nm.