Multiplexing using principal modes in spliced MMFs with mode dependent losses

Modal dispersion severely limits data rates in multimode fiber (MMF) links. The use of principal modes (PMs) in lossless MMFs mitigates the impact of modal dispersion over a large bandwidth and permit effective multiplexing due to their orthogonal nature. However, in fibers with mode-dependent losses (MDL), the principal modes experience different losses and are no longer orthogonal. In this paper, we consider the impact of MDL in spliced few-mode and large-core MMFs and evaluate the ergodic and 1% outage rates achievable over few-mode and large-core MMFs. Simulations using a model for MMF propagation reveal that, if knowledge of PMs are present at the transmitter, a significant amount of the fiber capacity can be obtained even when the fibers have splices with offsets of upto a few microns.