Fabrication and characterization of PZT/TiO(x)/SiO(2)/SiN(x)/SiO(2)/Si structure for acousto-optic device applications

Abstract

In this study, we fabricated the PZT/TiOx/SiO2/SiNx/SiO2/Si structure for acousto-optic (AO) device applications using the interaction of surface acoustic wave (SAW) and optical beam. SAW was generated using the inter-digital transducer (IDT) on PZT film, and optical beam (He-Ne laser) was guided in SiNx film using prism-coupling method. Two SiO2 layers were used for optical cladding layer, and TiOx for the buffer layer to prevent the inter-diffusion between PZT and SiO2 layers. In this structure, we measured insertion loss of -7dB at minimum point, resonance frequency of 17.6 MHz and sound wave velocity of 8800 m/s under impedance matching condition. We also measured optical propagation loss of the SiNx-film in both SiNx/SiO2/Si and PZT/TiOx/SiO2/SiNx/SiO2/Si structure for confirming the applicability of SiNx film to the waveguide layer.