Fast Photonic Switches with Ferroelectric Films

Abstract

Fir st prototypes of electrooptic (EO) planar deflector switches (PDS) are fabricated with hybrid integration on Si substrates. Planar optical modules, made in silica-on-silicon technology, consist of input and output waveguide microlenses facing each other and slab waveguides in between. The modules interconnect the input and output fibers with laterally collimated light beams less than 400 m in width at distances up to 100 mm with losses lower than 3 dB. Thin lead lanthanum zirconium titanate (PLZT) films with prism-shaped electrodes grown on SrTiO3 substrates form the deflector elements. The PLZT films are more than 10 m thick with EO coefficients about 40 pm/V. The deflector assembly technology provides chip vertical positioning accuracy better than 1 m. The deflector chips are attached to the optical substrates with thermocompression flip-chip bonding. The optical power losses of the modules with test silica chips can be as low as 3.6 dB. However, the lowest module losses achieved with PLZT are about 10 dB. The channel-to-channel switching operations are demonstrated at about 40 V and switching times less than 300 ns.