Coupled Star Network: A New Configuration for Optical Local Area Network

Takeshi OTA  

IEICE TRANSACTIONS on Communications   Vol.E75-B   No.2   pp.67-75
Publication Date: 1992/02/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Communication Networks and Service
star coupler,  LAN,  optical communication,  optical amplifier,  multimedia,  

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Theoretical network analysis of a network constructed of "Interconnectable Star Couplers" whose all diagonal elements of transmission matrix are zero is investigated. Under certain connection rules, Interconnectable Star Coupler can be connected each other without oscillation and ghost formation. The rules are: (1) Network should not contain any loop. (2)Only single port pair should be connected between neighbor star couplers. (3)Network shold not contain any usual star coulpler. "Coupled Star Network", which is constructed under the connection rules, is able to form Cascade Star topology, Stratified Star topology and their mixed topology. It is shown that the Coupled Star Network is equivalent to a large Interconnectable Star Coupler so that bidirectional communication, which can add confidentiality to the broadcasting bus and doubles communication capacity, is available. A new configuration of Coupled Star Network using passive Interconnectable Star Couplers and optical amplifiers is proposed. This network has two separated bidirectional communication channel which can be applied for so-called Multimedia LAN. As a result of comparison between Cascade Star topology and Stratifide Star topology, it is shown that the latter topology is superior to former topology, from the view point of signal degeneration and maximum round trip delay time. Cascade Star topology, however, is superior to Stratified Star topology from the angle of total fiber length. Accordingly, optimized network topology is thought to be mixed topology of these.