Adiabaticity-Engineered Compact Mode-Evolution-Based Symmetric Four-Mode Y-Junction at Wavelength 2.1 μm

We propose a mode-evolution-based symmetric four-mode Y-junction at wavelength 2.1 μm. Taper shape for the proposed device is designed using our novel method of adiabaticity engineering with radiation-loss reduction, providing 10 times shorter length compared to the linear taper. The proposed Y-junction is useful for on-chip switch-based mode-division multiplexed network.