Abstract: We disclose demultiplexing processing for an adaptive MIMO equalizer of a receiver of multiplexed communication signals implemented in a manner that significantly reduces the occurrence of singularities at the equalizer output without a significant concomitant increase in the required computational power. The receiver includes an equalizer controller that operates to dynamically track the degree of correlation of one or more pairs of equalized signals outputted by the MIMO equalizer and to use the tracking results to configure the MIMO equalizer in a manner that substantially prevents any two outputs of the MIMO equalizer from converging to the same state. In an example embodiment, the degree of correlation can be determined in a computationally efficient manner by identifying and comparing quadrants in which complex values produced at the different outputs of the MIMO equalizer are located over a plurality of time slots.

Abstract: An optical receiver having an electronic dispersion-compensation module with two parallel signal-processing branches configured to provide a greater range of dispersion compensation than that provided by a prior-art device of comparable implementation complexity. In an example embodiment, each of the signal-processing branches includes a respective bank of finite-impulse-response filters that are configured in accordance with a different respective approximation of the group delay that needs to be compensated. The two group-delay approximations used by the filter banks rely on different respective step functions, each having a respective plurality of quantized steps, with the transitions between adjacent steps in one step function being spectrally aligned with the flat portions of the corresponding steps in the other step function.

Abstract: An optical receiver having an electronic dispersion-compensation module with two parallel signal-processing branches configured to provide a greater range of dispersion compensation than that provided by a prior-art device of comparable implementation complexity. In an example embodiment, each of the signal-processing branches includes a respective bank of finite-impulse-response filters that are configured in accordance with a different respective approximation of the group delay that needs to be compensated. The two group-delay approximations used by the filter banks rely on different respective step functions, each having a respective plurality of quantized steps, with the transitions between adjacent steps in one step function being spectrally aligned with the flat portions of the corresponding steps in the other step function.