Dynamic holographic spectral equalization for WDM

We report a new technique for active management of wavelength division multiplexing (WDM) channels in an optically amplified telecommunications system, based on a polarization-insensitive holographic in-line wavelength filter. Results are presented for the control, amplification and equalization of five WDM channels spaced by 4 nm, Input signal power variations of 8.5 and 2.0 dB are reduced to 0.4 and 0.3 dB, respectively, by switching between two equalising holograms in 5 ms, with signals experiencing gains of up to 3.3 dB while undergoing equalization, An unused channel and amplified spontaneous emission noise from the erbium-doped fiber amplifier (EDFA) have also been suppressed by greater than 18 dB, This is the first demonstration of active holographic spectral equalization for WDM.