Optimization of silicon-on-insulator based optical switch using tapered waveguides

Optimized 2×2 switches based on silicon-on-insulator (SOI) were demonstrated. In the design, single mode rib waveguidesand multimode interferences (MMIs) are connected by tapered waveguides to reduce the mode coupling loss between thetwo types of waveguides. The average insertion loss of the switches is about -16.9 dB and the excess loss of one is measuredof -1.3 dB. The worst crosstalk is larger than 25 dB. Experimental results indicate that some of the main characteristics ofoptical switches are improved in the modified design, which is according with theoretic analysis. The novel design can beused to improve the characteristics of optical switch matrixes based on 2×2 switch units.