Adaptive minimum MSE controlled PLC optical equalizer for chromatic dispersion compensation

With the advent of very high-bit-rate optical communication systems (40 Gb/s and beyond) and the progressive transformation of the optical layer in a real networking layer, a channel-by-channel adaptive optical equalization will be needed. An adaptive optical equalizer for chromatic dispersion compensation, based on planar lightwave circuit (PLC) technology and controlled by a minimum mean square error (MSE) strategy, is proposed here. It is shown in a rigorous manner how the PLC parameters are to be adjusted and that the control algorithm is effective even with a few stages PLC equalizer, performing better than other nonadaptive control techniques. An analysis of the dynamic behavior of the equalizer shows that, in a realistic time-varying scenario, it can easily adapt to slow channel variations and is able to quickly restore a minimum MSE condition after an abrupt chromatic dispersion variation.