Controllable polarization electro-optic absorption graphene modulator

Abstract

Abstract Graphene, as two-dimensional material with many properties of the gate-voltage tunable Fermi-level and zero band gap, can be utilized for optical modulators by the integration with other material. In this work, an electro-optic modulator based on the fiber-surface waveguide and graphene capacitance has been proposed with the device length of 50 μm, featuring excellent controllable polarization modulation (polarization extinction ratio over 0.12 dB/μm), large modulation bandwidth of ∼40 GHz @ hBN and ∼25 GHz @ Al2O3, and energy consumption low to 11.5 pJ/bit for hBN and 4 pJ/bit for Al2O3. The polarization can be controlled by tuning the core radius from 130 nm for the TE polarized modulation with modulation efficiency over ∼2.56 dB V−1 (Al2O3) and ∼1.15 dB V−1 (hBN) to 170 nm for the TM polarized modulation efficiency up to ∼3.03 dB V−1 (Al2O3) and ∼1.3 dB/V (hBN). This work not only promotes the development of future polarization modulation technology, but also paves the way toward multifunctional fiber devices and systems.