Characterization of hydrometeor scattering effects and experimental measurements using near-infrared free-space urban links

The improvements of the instrumentation available within the free space optics (FSO) link set up in the Roman area (Italy) is illustrated together with FSO channel physical modelling activity. The wireless optical link at 1550 nm is 1.650 km long and has a transmission rate up to 1.5 Gbps. This link is intended to be, in the next future, the trunk sector of a convergent passive optical network (G-PON). Among particle scattering effects affecting the capacity of the optical channel, a focus is placed on raindrop and fog droplets. An evaluation of these atmospheric effects is illustrated and a comparison with measurements is carried out for some case studies of moderate and heavy rainfall. This becomes fundamental to evaluate the feasibility of such an approach in real telecommunications access scenarios, where the quality of service (QoS) and the quality of experience (QoE) must be always guaranteed.