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

We present a compact silicon-based 1×2 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 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mu$</tex-math></inline-formula>m × 42 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mu$</tex-math></inline-formula>m. A fast switching speed of 1.15ns is achieved along with a low power consumption of 15.3mW.