Compensation of crosstalk in optical spatial division multiplexing systems employing multiple-input and multiple-output processing

The development of digital coherent optical communication technology has boosted the system capacity close to the nonlinear Shannon limit imposed by the combination of additive noise and nonlinear distortion. In this context, spatial division multiplexing (SDM) has emerged as a promising solution to overcome such capacity limit. SDM systems, however, are affected by channel-dependent loss as well as by interchannel crosstalk. In this paper, we develop analytical expressions for the system capacity in presence of both impairments, showing that when multiple-input-and-multiple-output processing is implemented in the receiver side, the crosstalk can be compensated.