Hs. Seo et al., Simultaneous amplification and channel equalization using Raman amplifier for 30 channels in 1.3-mu m band, J LIGHTW T, 19(3), 2001, pp. 391-397
A new technique is proposed to simultaneously amplify signals and equalize
power unbalance caused by Raman-induced crosstalk among optical channels in
the 1.3-mum band. The crosstalk is induced in GeO2-doped silica fibers due
to the Raman-gain coefficient with a positive slope below the peak-frequen
cy shift of 440 cm(-1). Highly doped GeO2 silica fiber, however, shows a ne
gative slope across the band between 440 cm(-1) and 490 cm(-1). We propose
expansion of the Raman-gain band with a negative slope over the bandwidth o
f 150 cm(-1) using multiple pumps. Utilizing the negative gain slope of the
proposed band, simultaneous amplification and power equalization was theor
etically demonstrated for 30 channels in the 1.310-1.345 mum region without
external filters.