Record performance of parametric amplifier constructed with highly nonlinear fibre - Electronics Letters

The Raman pumps consist of 90 mW backward-propagating 1495 nm polarisation multiplexed pumps for the longer wavelength region, along with forward and backward 1410 nm polarisation multiplexed pumps for the shorter wavelength region. The 1410 nm forward pump is 150 mW and the backward pump is 2 10 mW. 50 km of nonzero dispersion shifted fibre with roughly 14.3 dB attenuation is used for transmission fibre. Because bidirectional pumps are used, the maximum Raman pump power at any local position is 300 mW. Fig. 6 shows total gain, Raman gain and equivalent NF (equivalent NF is defined as measured NF minus fibre attenuation). In addition to 100nm 20dB gain bandwidth, this amplifier also has the effect of flattening the noise figure with bidirectional pumping on the shorter wavelength region, thus keeping the equivalent NF less than 3.2 dB over 100nm. Compare this to the double-stage F-EDFA which has an NF distribution from 5.0 to 7.7 dB.