We study the problem of determining the minimum number of limited range wavelength converters needed to construct strictly, wide-sense, and rearrangeably nonblocking optical cross-connects for both unicast and multicast traffic patterns. We give the exact formula to compute this number for rearrangeably and wide-sense nonblocking cross-connects under both the unicast and multicast cases. We also give optimal cross-connect constructions with respect to the number of limited-range wavelength converters.

Constructing wavelength division multiplexing (WDM) multicast switches with inexpensive components and low complexity is an important problem in optical networking, as multicasting is one of the key requirements of emerging bandwidth-intensive applications such as video conferencing, video on demand and online gaming. In this paper we present several new cost-effective designs for constructing nonblocking WDM multicast switching networks. More specifically, we provide a wide-sense nonblocking switch architecture, which uses fewer semiconductor optical amplifiers than existing architectures. In addition, for the first time we have presented a rearrangeably nonblocking WDM switch architecture using array waveguide grating routers and wavelength converters.

Constructing wavelength division multiplexing (WDM) switches with cheap components and low complexity is an important problem in optical networking. Typically, there are two request models widely considered. In one model, a connection request asks to go from a wavelength on an input finer of the WDM switch to a particular wavelength on an output fiber. In the other, a connection only needs to get to a particular output fiber, irrespective of what wavelength it will be on. We give novel constructions of strictly nonblocking and rearrangeably nonblocking WDM switches for both request models using limited range wavelength converters and arrayed waveguide grating routers. We fully analyze their blocking characteristics. Our designs are all relatively simple and easy to be laid out, and are useful for both optical circuit-switching and optical packet/burst switching. As far as we know, these are the first of such constructions.