1% I ',I 1 I -. r( d.td%,fi(i r I-"[I 1 ' r -1. \/t' Abstract-The development of piezoelectric transducers based on periodically poled ferroelectrics domains is investigated.Optical quality Z-cut LiNb03 wafers have been used for the fabrication of test devices operating in the range 7 -70 MHz The fabrication process is detailed and characterization results are reported. A very good agreement between theoretical predictions achieved by periodic finite element analysis and experiments is observed, allowing for a precise identification of the excited modes.

In this paper, we present new results on the development of piezoelectric transducers based on periodically poled ferroelectrics domains. The fabrication of test devices operating in the range 50 -500 MHz has been achieved. Pure longitudinal modes are excited, yielding high frequency operation of test devices with easily achievable lithography process (20 and 10 µm periods). The dispersion analysis of our devices is reported and the capability of the proposed waveguide to support pure longitudinal modes along the plate radial dimension is emphasized

The authors propose and demonstrate a simple and novel method for fabrication of efficient Bragg grating reflectors at telecommunication wavelengths in titanium-indiffused lithium niobate single-mode channel waveguides. This technique is based on the patterned proton-exchanged process. The validity of the method is verified by the good agreement of the spectral responses and the Bragg phase-matching condition. Reflectivity as high as 94% at 1546 nm was measured with 4-mm distributed parameter waveguides in z-cut lithium niobate.