Star coupler based WDM switch employing tunable devices with reduced tunability range

High capacity star coupler based WDM switches require tunable devices with a wide tunability range beyond the reach of the present device technology. The Letter describes a new design principle for such WDM switches that incorporates available tunable devices that are short of the required tunability range. The proposed design, which is based on the conventional three-stage switch architecture, requires less hardware than previously needed, but at the cost of increased switch control complexity.