Gianpaolo Susanna

Time-Resolved Response of Polymer Bulk-Heterojunction Photodetectors

We have fabricated a polymer bulk-heterojunction photodetector from a (1:0.7) blend solution of poly(3-hexyl-thiophene) (P3HT) and 1-(3-methoxy-carbonyl)propyl-1-phenyl-(6, 6)C-61 (PCBM) in o-dichlorobenzene. Absorption spectrum, external quantum efficiency and current-voltage (I-V) curves, both in dark condition and under illumination of a narrowband green light-emitting diode (green-LED) with λem,peak center at 525 nm, were measured to characterize the photodiode behavior. Moreover, the time-resolved response under the green-LED stimulus modulated at 200 KHz has been measured. This result suggests the application of our device as organic photodetector for all-organic optical data link in low-cost plastic-optical-fiber-based systems.

Preliminary investigations of the effects of air turbulences on the performance of an indoor optical wireless link

Photonic technologies are becoming more and more necessary for data centre (DC) networks to meet the requirements of data transfer speed and energy saving. The use of optical hybrid wired/wireless solutions, where fibre links are coupled to free space optical links within the same DC facility can contribute to reduce the complexity of the network architecture and increase the efficiency of cooling. Although indoor optical wireless is immune by detrimental weather conditions on the free space optical link, the specific environmental conditions of a data centre room, such as strong local thermal variations and high intensities air flows, can introduce effects over the optical channel that can affect the link performance. The aim of this work is to provide a preliminary evaluation of the effects of controlled turbulences in terms of temperature and air flow speed on the power of the free space optical signal, with the purpose of enabling an initial understanding of the involved phenomena. Finally, the effects of the hot air flow-perturbed FSO link on the quality of a video service delivered on a photonic network are compared to a fully fiber-based link.