Design criterion of space-time codes for SDM optical fiber systems

The last two decades have known an exponential growth in the demand for network bandwidth. Since single mode fiber systems are approaching the nonlinear Shannon limit, multimode fibers (MMF) holds the promise to increase the capacity of optical transmission systems. Propagating modes through multimode fibers are affected by a non-unitary crosstalk known as mode dependent loss (MDL). The impact of MDL and its detrimental effect on the channel capacity was reported in many studies. Space-time coding already designed for wireless communications, was proved to mitigate the non-unitary effects of mode dependent loss. In this paper we derive an upper bound of the error probability of the optical channel affected by MDL, this upper bound yields the design criterion of space-time codes allowing total mitigation of MDL in space division multiplexed transmission systems.