REDUCED SWITCHING DELAY IN WAVELENGTH-DIVISION MULTIPLEXED 2-DIMENSIONAL MULTIPLE-PLANE OPTICAL INTERCONNECTIONS USING MULTIPLE-WAVELENGTH VCSEL ARRAYS

We calculate the expected number of internodal hops for a network esta blished with a wavelength division multiplexed (WDM) two-dimensional ( 2-D) multiple-plane optical interconnection. This WDM optical intercon nection incorporates WDM pixels consisting of multiple-wavelength vert ical-cavity surface-emitting laser (VCSEL) arrays and wavelength-selec tive detectors, The WDM interconnection can support simultaneous and r econfigurable communication among a network of nodes, Using the expect ed number of hops as a measure of internodal switching delay, we show that the integration of WDM into the interconnection results in a sign ificantly reduced delay as compared to single-wavelength systems, Subs tantial delay reduction results even when the number of wavelengths is small relative to the number of 2-D planes. We analyze the bus, dual- bus, and ring architectures since they define the means of communicati on between pixels, For each architecture, we analyze three configurati ons which provide each node access to i) an entire plane of pixels, ii ) a row (or column) of pixels, or iii) an individual pixel. When each network node has access to an entire plane of pixels, the proposed WDM interconnection incurs substantially shorter delay than single-wavele ngth optical interconnections. By allowing a node to access an entire row or column of pixels, the interconnection benefits from the incorpo ration of spatial division multiplexing (SDM) and the number of nodes connected can grow substantially with negligible added delay, Finally, when a node can access only a single pixel, a large number of indepen dent processors can be interconnected exhibiting far less switching de lay than other electronic or optical interconnections of comparable si ze.