Reconfigurable Fading Testbed for the Investigation of COTS Transceivers in OFLs

Optical feeder links (OFLs) between ground station and satellites are expected to be a key element of future sixth-generation three-dimensional (3D) networks. Indeed, the wide and unregulated bandwidth of the optical domain, combined with the high coverage offered by space networks, results fundamental to develop a broadband global connectivity, integrating both terrestrial and non-terrestrial network segments. However, OFLs are affected by channel impairments such as optical turbulence, leading to random fading of the received optical power. Thus, even if the development of OFLs could benefit from existing hardware produced for optical fiber-based networks, the capability of these components to counteract atmospheric fading must be investigated. To this aim, this paper presents a novel and fully reconfigurable experimental fading testbed which can be used to test commercial off-the-shelf components in laboratory. The proposed setup is exploited to investigate the performance of a link employing 10 Gigabit Ethernet transceivers and affected by turbulence-induced fading representative of a downlink OFL involving a low Earth orbit satellite.