Silicon Plasmon Modulators: Breaking Photonic Limits

Emerging communication applications anticipate a photonic roadmap leading to ultra-compact photonic integrated circuits. The objective is to design integrated on-chip electro-optic modulators EOMs that can combine both high modulation efficiency and low switching energy. While silicon-based EOMs have been demonstrated, they have large device footprints of the order of millimeters as a result of weak non-linear electro-optical properties. By deploying a high-Q resonator the modulation strength can be increased, however with the trade-off of bandwidth. Here we review some of our recent work and future prospects of hybrid plasmonic EOMs. We demonstrate a highperformance ITO-EOM in a plasmonic silicon-on-insulator (SOI) hybrid design. Remarkably, results show that an ultra-compact (3m) hybrid EOM deploying enhanced light-matter-interactions LMIs is capable of delivering an extinction ratio (ER) of about 1 dB/nm. This is possible due to a change of the ITO’s extinction coefficient by a factor of 136. Furthermore, a metric to benchmark electro-absorption modulators is provided, which shows that silicon plasmonics has the potential for high-end switching nodes in future integrated hybrid photonic circuits.