A Compact Silicon Based 1 × 2 MMI Switch Based on Carrier Injection Based Refractive Index Change

We present a compact silicon-based $1\times 2$ multimode interference (MMI) switch that utilizes carrier injection for optical switching. The mechanism involves selectively injecting carriers into designated regions of the MMI core via a p-i-n diode, inducing a refractive index change of –0.0423 under a 1.4 V bias. The device exhibits low crosstalk of –31.53 dB within a footprint of 7 $\mu$m × 42 $\mu$m. A fast switching speed of 1.15 ns is achieved along with a low power consumption of 15.3 mW.