Topology analysis of the optical fiber data buses for military vetronics

The physical performance imposed by topologies and access couplers in optical fiber data bus for military vehicle is analyzed. The comparison is in term of fiber required, average propagation delay, transmission loss, max bit rate, fault tolerance among four type topologies included bus, star, ring and dual ring. The results show that for 100 nodes, the star topology requires 3.8 times as much as fiber as a dual ring, but the average propagation delay of a dual ring is 3.3 times that of the star. For 10 nodes, the receiver dynamic range must be greater than 24 dB. If VCSEL and graded-index multimode fiber were adopted, the maximum bit rate reduces due to the fault tolerant access coupler used and depends on the number of nodes in the dual unidirectional bus or star topology. These results can provide reference for choosing topology and the type of access couplers that may be used in optical fiber data bus.