Wavelength-exchanging cross connects (WEX)-a new class of photonic cross-connect architectures

All-optical wavelength division multiplexing (WDM) networks are expected to realize the potential of optical technologies to implement different networking functionalities in the optical domain. A key component in WDM networks is the optical switch that provides the basic functionality of connecting input ports to output ports. Existing WDM switches make use of space switches and wavelength converters (WCs) to realize switching. However, this not only increases the size and the complexity of the switch but also bears heavily on the cost. In this paper, the authors propose a new class of photonic switch architectures called wavelength-exchanging cross connect (WEX) that provides several advantages over existing switches by enabling a single-step space switching and wavelength conversion and thus eliminating the need for a separate conversion stage. This greatly enhances the switch architecture by reducing its size and complexity. The new class of cross-connect architectures is based on the proposed concept of a wavelength-exchange optical crossbar (WOC). The WOC concept is realized using the simultaneous exchange between two optical signals. The proposed WEX architecture is highly scalable. To establish scalability, the authors present a systematic method of developing instances of the switch architectures of an arbitrary large size.