All-oPtical prOcessing in few-mode FIbreS – APOFIS

In order to face the non-stop growing demand of data-traffic in nowadays optical networks, a new milestone in the landscape of optical communications has emerged in the last few years, i.e. space-division multiplexing (SDM). In SDM systems, each fibre core or mode represents an independent channel, which in principle allows to largely overcome the capacity limit imposed on traditional single-mode platforms. The challenge is now to enable the deployment of SDM in a near future. To this aim, the APOFIS project will address key issues for SDM implementation by exploiting nonlinear effects in few-mode fibres. In particular, novel approaches for crosstalk management, amplification and propagation of SDM signals will be demonstrated. Thanks to these solutions, stringent constraints of SDM and associated cumbersome offline processing’s should be relaxed, thus allowing real-time transmissions and making SDM a compelling technology to deploy. More precisely, based on counter-propagating interactions between multimode signals, APOFIS will establish a general concept of multi-dimensional condensation of light in multimode fibres. On these basis, several modal functionalities will be developed such as all-optical mode cleaner, crosstalk-free transmission, frequency/mode converter as well as spatial routing and switching operations. Wideband multimode parametric amplifiers will be also designed based on inter- and intra-modal interactions, so as to exceed the current limits of Erbium-based amplifiers. Furthermore, we will report the first implementation of data transmission through spatial domain-walls and exploit these symbiotic structures to highlight an unfamiliar phenomenon of spatial segregation. Finally, beyond the direct impact of APOFIS on optical communications, developing innovative technologies based on multimode fibres could have a large impact on numerous fields of science and engineering involving optical spatial modes.