Ricerc@Sapienza

This work presents analysis and development of an evanescent waveguide sensor system,
which integrates an amorphous silicon photodiode and a glass-diffused waveguide. Design of the
system includes a study of thickness and refractive index of the transparent electrode of the diode,
which are crucial parameters for the optimization of the optical coupling between the waveguide
and the photodetector. Preliminary electro-optical measurements on the fabricated device show

This paper presents the analysis and development of an evanescent waveguide sensor system, based on a hydrogenated amorphous silicon (a-Si:H) photodiode and a double ion-exchanged waveguide diffused in a borosilicate BK7 glass substrate. The a-Si:H sensor is a p-doped/intrinsic/n-doped diode, with a metal top electrode and an indium tin oxide (ITO) transparent bottom contact. Simulations on the confinement of a monochromatic light in a channel waveguide and its coupling into a thin-film photodetector were performed using COMSOL Multiphysics.

We present a new class of photonic devices in which light is confined in channel waveguides, named LC:PDMS, made of a nematic liquid crystal (LC) core in a poly(dimethylsiloxane) flexible substrates. Monte Carlo techniques have been used to study LC orientation. Homeotropic alignment of LC molecules has been observed without any applied electric field. A theoretical study of LC orientation under an electric field between coplanar gold electrodes deposited by electroplating has been carried.