Intercore–gain–crosstalk in multicore fiber amplifiers for telecommunication applications

Spatial division multiplexing is the only currently known technique to cope with the forecasted demand for capacity in the long term. Of particular interest is its implementation as multicore fiber system, which offers further capacity increase while simultaneously reducing cost and energy consumption per throughput. Essential components in such a transmission system are cladding pumped multicore amplifiers, which allow for signal amplification in multiple cores via a single uncooled multimode pump. However, above mentioned advantageous features could come with the detriment of a coupling of the pump powers available for amplification in the different cores. The resulting gain crosstalk is investigated by means of simulations for various signal power distribution schemes across the cores. In particular, gain variations in all cores are demonstrated to be negligible for signal power changes in other cores.