New Bounds on the Feedforward Design of Optical Output Buffer Multiplexers and Switches

Xiaoliang WANG  Xiaohong JIANG  Susumu HORIGUCHI  

IEICE TRANSACTIONS on Communications   Vol.E92-B   No.4   pp.1183-1190
Publication Date: 2009/04/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E92.B.1183
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Switching for Communications
optical buffer,  switched delay line (SDL),  fiber delay line (FDL),  multiplexer,  output buffer switch,  

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We focus on non-conflicting construction of an optical multistage feedforward network to emulate the N-to-1 output buffer multiplexer by using switched fiber delay line (SDL). In [1], Y.T. Chen et al. presented a sufficient condition (an upper bound) for the number of delay lines required for such a multiplexer with variable length bursts. In this paper, we first give an improved upper bound. Then we develop a framework to construct an arrival case of bursts which can be used to achieve a necessary condition (a lower bound). These results are further extended to the feedforward construction of N-to-N output buffer switch. Through simulation and performance comparison, we find that the new bounds can significantly decrease the hardware cost for constructing both the feedforward SDL-based multiplexer and output buffer switch while still provide the same performance as that of the old ones.