NEW ARCHITECTURES FOR OPTICAL TDM SWITCHING

Time division multiplexing (TDM) is a natural multiplexing format for many services that will be found in future optical telecommunications networks, such as high definition television (HDTV) and videophone. Th is paper is the first part of a systematic theoretical study of archit ectures for optical TDM switching, using lithium niobate optical switc hes, with optical fiber delay lines for storage. The architectures all ow the bitrate and wavelength transparency of these devices to be expl oited. A technique involving recursive definition and proof is used to define the networks, which are mathematically related to Benes and Wa ksman networks. This produces architectures that are very different fr om existing optical TDM networks. They exhibit economical use of compo nents, which reaches the theoretical minimum in some cases. Also, the use of ''feed-forward'' rather than ''feed-back'' delays give these ne tworks superior crosstalk performance and more uniform attenuation tha n existing designs. Dilated Benes networks are generalized so that all the networks proposed here can be dilated. This drastically reduces c rosstalk at the expense of roughly doubling the number of switches. At tenuation is also studied, and it is found that by constructing the ne twork properly, it can be reorganized onto only a few substrates, grea tly reducing attenuation. Network architectures both having and lackin g frame integrity are considered.