High efficiency graphene–silicon hybrid-integrated thermal and electro-optical modulators†

Abstract

Graphene modulators are considered a potential solution for achieving high-efficiency light modulation, and graphene–silicon hybrid-integrated modulators are particularly favorable due to their CMOS compatibility and low cost. The exploitation of graphene modulator latent capabilities remains an ongoing endeavour to improve the modulation and energy efficiency. Here, high-efficiency graphene–silicon hybrid-integrated thermal and electro-optical modulators are realized using gold-assisted transfer. We fabricate and demonstrate a microscale thermo-optical modulator with a tuning efficiency of 0.037 nm mW⁻¹ and a high heating performance of 67.4 K μm³ mW⁻¹ on a small active area of 7.54 μm² and a graphene electro-absorption modulator featuring a high speed data rate reaching 56 Gb s⁻¹ and a low power consumption of 200 fJ per bit. These devices show superior performance compared to the state of the art devices in terms of high efficiency, low process complexity, and compact device footage, which can support the realization of high-performance graphene–silicon hybrid-integrated photonic circuits with CMOS compatibility.