2 × 2 optofluidic switch chip with an air shutter.
A 2×2 optofluidic switch chip with an air shutter is proposed. It has a simple structure, small volume, small crosstalk, large extinction ratio, small polarization-dependent loss, and broad operation waveband (400-1700 nm). This 2×2 switch chip has good scalability and can form a number of optical switches by using different microfluidic driving technologies. The research results show that the microchannel width has great influence on the switch performances in "on" state, where the comprehensive performances of the optical switch are the best at 4.0 μm width. By replacing the original symmetrical structure with an optimized semi-tapered structure, the switch performances are further improved. After the structure and parameters are optimized, for 1310 nm wavelength, the insertion losses of the proposed switch are 0.41 dB in "on" state and 0.15 dB in "off" state, the extinction ratios are 52.5 dB in "on" state and 28.3 dB in "off" state, and the crosstalks are -28.8  dB in "on" state and -52.6  dB in "off" state.