Mode Switch for On-Chip Optical Interconnects using Multimode Interference Couplers

We design a 4×4 single-mode optical switch which is capable of switching four fundamental modes from four input ports to any of the four output ports. The proposed device consists of two 4×4 multimode interference couplers on an SOI platform with 220 nm thick Si layer. Mode signals selected at the desired output were determined by four phase shifters placed between two MMIs. Through numerical simulation method BPM combined with EIM method, we evaluate optical conversion efficiency when transmitting optical mode signals at any input and measuring optical power at outputs. At 1550 nm central wavelength, insertion loss is always less than 0.1 dB and below 1.6 dB in the entire C band. Furthermore, the crosstalk is always from -110 dB to -50 dB in a range of band of 35 nm.