Reducing the Mode Dependent OSNR Requirements in SDM Systems due to Nonlinear Effects by Using Adaptive Symbol Rates

Abstract:
We examine the mode dependent requirements on the optical signal-to-noise ratio (OSNR) in a space-division multiplexed (SDM) system which are caused by nonlinear effects. Higher order modes exhibit smaller nonlinear coupling coefficients than the lower order modes. Therefore, a lower OSNR is required for an error-free data transmission via the higher order modes. We analyze the OSNR requirements in a SDM system using numerical simulations. A SDM system with 6 linearly polarized mode groups and 10 spatial channels, respectively, is considered. Our investigations show the OSNR requirements for each mode for varying transmission distances. We demonstrate how the mode dependent OSNR requirements can be adjusted to each other by the appropriate selection of the symbol rate for each mode. Thereby, the capacity of the SDM system can be increased.