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

We present the design of an integrated optoelectronic device based on an evanescent waveguide sensor with a-Si:H photodiodes and ion-exchange diffused glass waveguides for on-chip biomolecular detection.

Here we present the design of an amorphous silicon photodetector integrated with an ion-exchanged waveguide on the same glass substrate in order to obtain an evanescent waveguide sensor for on-chip biomolecular recognition in Lab-on-Chip applications. We studied the behaviour of a monochromatic light in a channel waveguide and its coupling into the thin-film sensor, using COMSOL Multiphysics. Simulations show that the presence of the photodiode’s insulation layer and transparent electrode strongly affects the coupling efficiency between the waveguide and the sensor.