Photonic quasi-crystal fiber electro-optical modulator

Abstract

The integration of graphene with optical fiber is considered to be a new interdisciplinary research hotspot for functional fiber. In this paper, an electro-optical modulator based on a six-fold Stampfli-type photonic quasi-crystal fiber is theoretically proposed with a sandwiched graphene/hBN/graphene film covering all the hole walls. This design exhibits a strong light-matter interaction with an excellent modulation depth of ∼64 dB mm-1 at 1550 nm by applying an external bias voltage (below 30 V) on both graphene layers. As the Fermi level of the graphene changes with voltage, the fiber shows “On” and “Off” states, serving well as an optical switch. For the modulator performance, the dependence of modulation depth on multiple factors is studied in terms of the layer numbers of graphene and hBN films, the fiber length, the incident wavelength, and the structure parameters. Interestingly, an attenuation peak originating from the surface plasmon resonance appears, showing a linear relationship between the resonant wavelength and the Fermi level. This design provides a viable solution for the integration of photonic quasi-crystal fiber and graphene, and holds great promise for future all-optical systems.