Adaptive PAM-4/PAM-8 graphene-based electro-optical modulator integrated into a polymer waveguide platform for data-center communication

Abstract

This paper presents a new concept of a graphene-based adaptive modulator for multilevel amplitude modulation on polymer technology platform. This component consists of an electro-optical modulator with a distributed five segments capacitive structure, based on two single-layers of graphene (SLG) and a thin layer of silicon nitride (Si3N4) in the form (SLG-Si3N4-SLG), which shows a dynamic configuration of the modulation scheme, PAM-4/PAM-8, by the applied logic voltage sequence (3Vpp) for an operating wavelength at 1550 nm. Considering an extinction ratio of 5.6 dB for PAM-4, and 6.0 dB for PAM-8, a compact device with 179.6 µm total length, and the maximum simulated cut-off frequency of 48.12 GHz with 122.9 fF of capacitance and total device resistance of 26.9 Ω, were achieved. This cut-off frequency results in a transmission rate of 96.24 Gbps at PAM-4 and 144.4 Gb/s at PAM-8. The simulated insertion loss is 12.0 dB (PAM-4) and 11.5 dB for PAM-8, and the power consumption is 0.54 pJ/bit for PAM-4 and 0.81 pJ/bit for PAM-8. Combining an innovative design with the unique electro-optical characteristics widely demonstrated by the materials used in the construction of the proposed adaptive device, allows it to be seen as a candidate to contribute to the nanotechnology integration and high-performance communication requirements.