Digitally tunable optical filters using arrayed-waveguide, grating (AWG) multiplexers and optical switches

Two novel configurations for digitally tunable optical filters based on arrayed-waveguide grating (AWG) multiplexers are described in detail with emphasis on the connection of the AWG multiplexer and optical switches. Performance comparisons show that conventional configurations are disadvantaged by the switch size required and loss imbalance among the optical frequency-division-multiplexed (FDM) channels; the proposed configurations require only O(root N) switch elements to select one of N FDM channels, and the loss imbalance is lower by up to 75% in decibel.