INTEGRATED PLZT THIN-FILM WAVE-GUIDE MODULATORS

In this paper we report field-induced spatial variations of outcoupled light in integrated IT0/PLZT/Si02/Si and IT0/PLZT/Si02/GaAs waveguiding structures, where the SiO2 layer acts as a buffer layer between the semiconducting substrates and PLZT, facilitating the support of TE and TM waveguide modes. Analysis of the various TE and TM modes is achieved using a prism out-coupling method. An electric field applied transversely to the propagation direction using the transparent ITO electrode induces a change in the effective indices of the waveguide modes which in turn causes an angular variation in the prism outcoupled modes. We have demonstrated an angular shift as large as 0.5 with a calculated field strength of 300 V/mm. The angular variation in the films display a quadratic relation to the applied field. The observed modulation can be explained in terms of a change in the effective index due to electro-optic effects in the PLZT film and/or possibly electrostrictive effects in the film layers. © 1991, Taylor & Francis Group, LLC. All rights reserved.