Sandwiched graphene/hBN/graphene photonic crystal fiber with high electro-optical modulation depth and speed
Graphene-photonic crystal fiber (PCF), integrating the broadband optical response and electro-optic tunability of graphene with the high-quality waveguide capacity and easy-integrability of PCF, has been proven to be an important step towards multimaterial multifunctional fiber and all-fiber integrated circuits. However, the reported electro-optic modulator based on directly-grown graphene-PCF suffers very low response speed (below 100 Hz) due to the slow response of ion liquid. Here, we propose a new functional PCF with sandwiched graphene/hBN/graphene (Gr/hBN/Gr) attached on the hole walls of the fibers, and theoretically demonstrate that the in-line modulator based on it can achieve simultaneously single-mode transmission ranging from 1260 nm to 1700 nm (covering all optical communication band), signiﬁcant modulation depth (e.g. ~42 dB/mm at 1550 nm) and high modulation speed (up to ~0.1 GHz). Furthermore, various device functions can be designed by changing the structure of fiber, including the length, the hole diameter and the layer numbers of graphene and hBN films. This proposed approach directs a viable path to high-performance all-fiber devices based on hybrid two-dimensional material optical fibers.