Optical communications is the linchpin of modern communications delivering vast majority of the online traffic worldwide at the terabit-per-second rate. However, an exponential growth of this traffic requires proper increase in transmission rate, which, in turn, puts more pressure on finding new technological solutions to meet these demands. A possible direction of this search is application of plasmonics. Plasmonics has the potential to combine the best properties of both electronic and photonic worlds leading to the development of new units of optical systems in nanoscale footprints. Application of plasmonics in optical communications would lead to integration of plasmonic circuitry with digital electronics, which in turn would open new opportunities in research applications and lay the foundation for the next generation digital technology. This paper is the attempt to make one more step in this direction. Specifically, we propose the structure for plasmonic field modulation and demodulation under two conditions: (1) The work is done for narrow-band coupling conditions and (2) graphene is used as an intermediate layer between the conductor and the cover to increase the coupling efficiency at the 1550-nm wavelength. The results include a unique description of the plasmonic coupling and resonance peak for the proposed structure and analysis of the enhancement in modulation performance caused by the insertion of the graphene layer in the plasmonic structure. The possible applications of the proposed structure are also considered.