Graphene-boosted ultra-wide band reconfigurable optical switch for SOI-based telecom applications: A numerical study

¹ Department of Electrical Engineering and Information Technology (DIETI), University of Naples Federico II, Via Claudio 21, 80125 Napoli, Italy
² Institute of Applied Sciences and Intelligent Systems (ISASI-CNR), Via P. Castellino n. 111, 80131 Napoli, Italy
³ Mediterranea University of Reggio Calabria, DIIES Dept., 89124 Reggio Calabria, Italy
⁴ Open Fiber S.p.A., Via Laurentina 449, 00142 Roma, Italy

^* Corresponding author: author@e-mail.org

Published online: 31 October 2024

Abstract

In this work, we propose the design of a compact optical switch featuring a wide bandwidth of 360 nm, suitable for telecom operations. The switch is a passive 3dB splitter realized through a Y-branch, electrically activated via a graphene/insulator/graphene (GIG) capacitor embedded within the rib waveguide (WG). The capacitor itself is embedded within an SOI-based hybrid WG composed of crystalline (c-Si) and hydrogenated amorphous silicon (a-Si:H), with the GIG between the two layers. Such a photonic structure optimizes the light-matter interaction and enables a compact device with a length of only 100 μm. By applying a voltage bias to the graphene layers, we achieve the condition necessary for efficient data transmission through the WG. Indeed, the electrical doping of graphene enables the modulation of optical losses within the waveguide, ranging from total light absorption to up to 70% transmission. The simplicity and ease of fabrication of this innovative design offer significant advantages for integration into existing photonic circuits. Its wide bandwidth allows compatibility with a variety of telecom wavelengths, providing flexibility in network configurations. Consequently, this compact optical switch presents a promising solution for modern data communication needs, demonstrating a balance between efficiency and scalability.