Optimizing epsilon-near-zero based plasmon assisted modulators through surface-to-volume ratio

Plasmonic-based integrated nanophotonic modulators, despite their promising features, have one key limiting factor of large insertion loss (IL), which limits their practical potential. To combat this, we utilize a plasmon-assisted approach through the lens of surface-to-volume ratio to realize a 4-slot based EAM with an extinction ratio (ER) of 2.62 dB/µm and insertion loss (IL) of 0.3 dB/µm operating at ∼1 GHz and a single slot design with ER of 1.4 dB/µm and IL of 0.25 dB/µm operating at ∼20 GHz, achieved by replacing the traditional metal contact with heavily doped indium tin oxide (ITO). Furthermore, our analysis imposes realistic fabrication constraints, and material properties, and illustrates trade-offs in the performance that must be carefully optimized for a given scenario.