OPTICAL WAVE-GUIDES FOR EVANESCENT FIELD SENSING

A new fabrication process of ion-exchange waveguides well suited for i ntegrated-sensor applications is presented. The process consists in bu rying each extremity of the waveguide few microns below the surface wh ile its central region is located at the surface. For a single-mode wa veguide at 785 nm, we measured propagation losses of 0.13 dB/cm for th e buried portion, 2.80 dB/cm for the surface portion, and losses of 0. 40 dB for the transition region. For this structure, we also observed a deformation of the fundamental mode. The proposed method is easy to implement and permits one to control precisely the topography of the e laborated waveguides.