Experimental demonstration of active equalization and ASE suppression of three 2.5-Gb/s WDM-network channels over 2500 km using AOTF as transmission filters

By using acoustooptic tunable filters with active feedback, we have experimentally demonstrated the dynamic channel-power equalization of the nonuniform EDFA gain as well as interchannel ASE suppression. The AOTF's have multiple independent passbands and act as dynamic wavelength-dependent loss elements. After 2500 km, the power differential is reduced from over 20 dB to /spl sim/1 dB for three 2.5-Gb/s WDM channels covering an /spl sim/8-nm wavelength range, and a 10/sup -9/ BER can be achieved for all channels.