| 摘要 |
PURPOSE:To make the reduction in the branching capacity compatible with the suppression of the effect due to multiple reflection in the optical branching device used for an optical distribution transmission system distributing and transmitting a frequency multiplexed signal. CONSTITUTION:The demultiplexer is made up n-stage of cascade connection (n is a natural number being 2 or over) of 2X2 branching device 102 and reflection reduction processing is applied to all of open terminals 103 of the 2X2 branching devices 102. Furthermore, the length of a pig tail fiber 109 of an output terminal is selected to be 7m or over, the length of a pig tail fiber 108 of an open terminal at a final stage is selected entirely to be 6m or over, and the length of a pig tail fiber of an input terminal is selected to be 20.2-2.2nm. Thus, the effect of multiple reflection is suppressed and the length of the interconnection fiber 106 interconnecting the 2X2 branching devices 102 and the length of the pig tail fiber 107 for open terminals other than that of the final stage is selected to be a required minimum length, then the capacity of the demultiplexers is reduced. |
