Abstract
Current and future parallel processing systems require high bandwidth interconnects to satisfy the communication demands. Optical technologies have been proposed to address the bandwidth limitation of electrical bus systems. Specifically, during the past decade, several optical bus parallel models have been proposed, together with a suite of basic and advanced algorithms. One of the more popular optical bus models is the Linear Array with Reconfigurable Pipelined Bus System (LARPBS), appearing in 1996. Since then, many publications present mostly theoretical work concerning LARPBS algorithms, and only limited comments regarding the implementation of this model have been noted. This paper assesses the realistic and practical nature of the LARPBS optical bus parallel model with respect to recent available optical technologies. An optical power and signal loss analysis for the LARPBS model is conducted. A straight forward implementation of the bus model without amplification of optical signals suggests high losses that limit the number of processors to between eight and twelve. Nevertheless, this work also suggests that variations in the architecture may lead to more practical parallel systems.

Les systemes de traitement parallele, presents et futurs, necessitent une interconnectivite ti haut debit qui satifasse aux besoins de communication. Des technologies basees sur l'optique ont dejti ete proposees pour palier ti la limitation de debit des systemes electroniques ti architecture bus. Plus precisement, plusieurs systemes paralleles ti bus optique ont ete mis de l'avant au cours de la derniere decade, lesquels sont accompagnes par des algorithmes de traitement plus ou moins avances. Un des systemes optiques les plus connus est le "Linear Array with Reconfigurable Pipelined Bus System" (LARPBS) qui afait son apparition en 1996. Depuis lors, plusieurs articles theoriques ont portes sur les algorithmes LARPBS, mais on y trouve peu d'informations sur l'implementation de tels systemes. Le present document evalue le realisme et les aspects pratiques dy systeme parallele LARPBS ti bus optique en regard des technologies optiques recentes. On y effectue une etude de la perte de puissance et de signal optique pour le systeme LARPBS. Une implementation simple du systeme bus, sans amplifiation du signal optique, montre de fortes pertes qui limitent le nombre de processeur ti un nombre variant entre huit et douze. Neanmoins, notre etude donne ti penser qu'une modification de l'architecture pourrait conduire ti la mise au point de systemes paralleles plus realistes.