CROSSTALK AND CHANNEL SPACING IN A COHERENT MULTICHANNEL SYSTEM USINGERBIUM-DOPED FIBER AMPLIFIERS

The influence of optical amplification with an erbium doped fibre ampl ifier (EDFA) on coherent multichannel (CMC) transmission is investigat ed experimentally. We found that exactly the same crosstalk/signal rat io can be tolerated in a CMC-system with and without EDFA. We 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 (h omogeneous) gain saturation. For deep saturation of the EDFA an increa se of the noise figure is expected. We conclude that EDFA noise and cr osstalk can be considered independent additive (Gaussian) noise source s to the system noise.