Interaction of linear mode coupling and nonlinearity in optical space division multiplexed systems

In this paper simultaneous transmission of five QAM-modulated mode channels in a single-core fiber with Kerr nonlinearity properties is investigated. It is shown analytically and by means of simulation that the presence of strong linear mode coupling leads to an increase of nonlinear impairments. In the weak-coupling regime the interaction result has a random nature and can also lead to an increase of nonlinear impairments. The distribution histogram of the difference between rms of nonlinear impairments in the case of presence and in the case of absence of linear mode coupling for the weak-coupling regime is obtained.