Simulation of electro optic modulators based on plasmonic directional couplers

In this paper, a new concept and geometry are proposed for plasmonic modulators, whose operation is based on the coupling between two plasmonic slots. An electro-optic polymer is exploited as an active material, and the device can be implemented within a Silicon Photonics platform. The device operates at 1550 nm wavelength, typical of data center or long-haul telecommunication systems. For a device length of around 16 μm, the simulated extinction ratio and optical insertion loss are 20.98 dB and 4.26 dB, respectively. Both performances compare favourably with those of Mach-Zehnder plasmonic modulators from the literature. The simulation is based on the Time Domain Finite Differences (FDTD) and Finite-Difference Eigenmode (FDE) methods.