Fabrication and demonstration of 1 x 8 silicon-silica multi-chip switch based on optical phased array

We experimentally demonstrated a 1 x 8 silicon-silica hybrid thermo-optic switch based on an optical phased array using a multi-chip integration technique. The switch consists of a silicon chip with optical phase shifters and two silica-based planar lightwave circuit (PLC) chips composed of optical couplers and fiber connections. We adopted a rib waveguide as the silicon waveguide to reduce the coupling loss and increase the alignment tolerance for coupling between silicon and silica waveguides. As a result, we achieved a fast switching response of 81 [mu]s, a high extinction ratio of over 18 dB and a low insertion loss of 4.9-8.1 dB including a silicon-silica coupling loss of 0.5 + or - 0.3 dB at a wavelength of 1.55 [mu]m.