Towards high capacity fibers for space and mode division multiplexed transmission

The demand for capacity is growing exponentially with about 40–60% per year passing the installed network capacity. For the last two decades the transmission capacity per fiber has increased by more than three orders of magnitude: Single channel (wavelength and polarization) electronically time-division multiplexed (ETDM) transmission showed a growth of one order of magnitude over the last two decades reaching 100 Gb/s; and multi-channel wavelength division multiplexing (WDM) increased the transmission capacity for a decade with a growth rate of 78% over the last decade, reaching more than 10 Tb/s. However, WDM has been leveling off since the turn of the millennium due to the full exploitation of the EDFA gain bandwidth and the lack of active ions in silica able to cover the full fiber bandwidth. Research in the last years has focused on coherent detection combined with powerful digital signal processing thus upgrading the installed fiber network to increase the available capacity per fiber. Although 100 Tb/s have recently been demonstrated, additional channels dimensions (on top of wavelength and polarization) will be required to avoid the capacity crunch and to keep up with the increase of capacity demand in the decades to come. As breakthrough technologies emerge space division (SDM) and/or mode division multiplexing (MDM) with the development of novel fibers, novel multiplexing and de-multiplexing components, and novel signal processing techniques. In this workshop, we will review and discuss some of the emerging technological options and consider their potential: Development of different types of multi-core fibers, allowing for coupling or suppressing the coupling between cores; few-mode and multimode fibers; multiplexing and de-multiplexing of optical signals with these novel fibers; signal processing schemes; and the combination of different multiplexing technologies for transmission.