Alignment of Free-Space Coupling of Few-Mode Fibre to Multi-Mode Fibre using Digital Holography

Off-axis digital holography is used to align a few-mode fiber to a multi-mode fiber in a free-space optical setup. Alignment based on power coupling measurements alone cannot guarantee low mode-dependent loss. The proposed alignment method enables reliable fiber coupling with low mode-dependent loss and crosstalk

1 Tbit/s/λ Transmission Over a 130 km Link Consisting of Graded-Index 50 μm Core Multi-Mode Fiber and 6LP Few-Mode Fiber

We demonstrate 1 Tbit/s/λ single-span transmission over a heterogeneous link consisting of graded-index 50 μm core multi-mode fiber and 6LP few-mode fiber using a Kramers-Kronig receiver structure. Furthermore, the link budget increase by transmitting only three modes while employing more than three receivers is investigated