On the Gaussian Pulse Propagation Through Multilayer Graphene Plasmonic Waveguides - Impact of Electrostatic Screening and Frequency Dispersion on Group Velocity and Pulse Distortion

In this paper, we analytically describe the characteristics of propagating and diffusive plasma waves in multilayer graphene heterostructures targeted toward implementing on-chip interconnects. When the effect of collision-dominated resistance of the graphene sheet is negligible, the plasma waves propagate through the media without pulse reshaping. However, in the presence of electron scatterings due to phonons and charged impurities in the sample, the plasma waves acquire a diffusive character and undergo significant frequency-dependent pulse reshaping. We analytically model the propagation speed and pulse-width distortion of a narrow-band Gaussian signal centered at THz frequencies by accounting for the finite electrostatic screening between the multiple layers of graphene. The consequences of signal distortion and attentuation on limiting the signal bit-rate and the impact on energy dissipation are quantified. A partition length of the plasmonic waveguide that distinguishes between LC - and RC-dominated regimes of signal transport is derived. For on-chip interconnect application, the upper bound on the propagation length of plasma waves is determined by both the energy dissipation and the bit-rate requirement of the interconnect infrastructure. Upon comparison with on-chip electrical interconnects, we identify the energy budget that can be allocated toward plasmonic transceivers, such that the overall plasmonic communication is more energy efficient compared to electrical communication.