Impact of Inter-Core Loss and Gain Equalization on Transmission Performance in Multi-Core Systems

Hybrid pumping schemes allow for equalizing transmission performance across the cores of a multi–core fiber based transmission system in the presence of fiber loss variations between the cores and core–dependent gain of the involved multi–mode pumped optical amplifiers. Power equalization by distributed Raman amplification comes with improved noise characteristics, but leads to reduced signal–to–interference ratio due to increased crosstalk. In an experimental setup, compensating loss in the outer cores of a 50km long trench–assisted 7–core fiber with this approach is shown to lead to an optical signal–to–noise ratio (OSNR) penalty increase by around 30% in the center core.