Optically-reconfigurable phase change material nanoantenna-embedded metamaterial waveguide

Heterogeneous integration of phase change materials (PCM) into photonic integrated circuits is of current interest for all-optical signal processing and photonic in-memory computing. The basic building block consists of waveguides or resonators embedded with state-switchable PCM cells evanescently coupled to the optical mode. Despite recent advances, further improvements are desired in performance metrics like switching speeds, switching energies, device footprint, and fan-out. We propose an architecture using resonant metamaterial waveguides loaded with Ge<inf>2</inf>Sb<inf>2</inf>Te<inf>5</inf> (GST) nanoantenna, and present a numerical study of its performance. Our proposed design is predicted to have a write energy of 16 pJ, an erase energy of 190 pJ (which is three to four times lower than previous reports), and, an order of magnitude improvement in the write-process figure-of-merit. Additional advantages include lowered ON state insertion loss and GST volume reduction.