Compact, broadband, and low-loss multimode optical switch based on phase-change material for mode division...

Mode-division multiplexing (MDM) technology is one of the suitable approaches to increase data transmission capacity in photonic integrated circuits. Multimode optical switches play an important role in MDM interconnection networks. In this article, we present a multimode on-off optical switch using Ge₂Sb₂Se₄Te₁ phase-change material for the first two TE modes (TE0 and TE1) and the first two TM modes (TM0 and TM1) in a wide wavelength range between 100 nm to around 1550 nm. The 3D finite-difference time-domain simulations indicate that for each propagating mode across the bandwidth, the insertion loss and extinction ratio are less than 0.80 dB and more than 20.21 dB, respectively. The proposed switch has a compact footprint of 10.7µm×3µm. The presented switch also tolerates a ±20nm change in the waveguide width, a ±10nm silicon waveguide height deflection, and a ±5nm GSST thickness variation with an insertion loss lower than 0.91 dB and an extinction ratio higher than 19.04 dB.