Crosstalk and channel spacing in a coherent multichannel system using erbium doped fibre amplifiers

The influence of optical amplification with an erbium doped fibre amplifier (FDFA) on coherent multichannel (CMC) transmission is investigated experimentally. The authors found that exactly the same crosstalk/signal ratio can be tolerated in a CMC-system with and without EDFA. They observed no noise floor nor other effects caused by spectral broadening due to the fibre amplifier phase noise. The main influence of the EDFA is (homogeneous) gain saturation. For deep saturation of the EDFA an increase of the noise figure is expected. They conclude that EDFA noise and crosstalk can be considered independent additive (Gaussian) noise sources to the system noise.<
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