| 摘要 |
PROBLEM TO BE SOLVED: To suppress the junction loss of an up signal, to eliminate a difference between the transmission/reception levels in up/down directions and the realize light transmission without waste by arranging optical star couplers between a transmission part and a signal multiple means in a subscriber terminal equipment, and inputting light signals which the signal multiplex means outputs to a reception means in parallel. SOLUTION: Mi -pieces of optical network devices 1-1 to 1-T are connected to the subscriber terminal equipment 3 by plural optical fibers through mi branching optical star couplers 2-i. It is T=Σmi (i=1-n). The up signal from the optical network device 1-2 reaches the reception part 6 through the optical star coupler 2-i. A down signal from the transmission part 5 is branched into n-pieces of signal in an n-branch optical star coupler 7 and they are branched into T-pieces of signals in the branch optical start coupler 2-i through an up/ down signal multiples circuit array 4. Then, they reach the optical network devices 1-1 to 1-T. The difference of the transmission line is a branch loss, and T>mi when (n) is more than 2. Then, the loss of the up signal is smaller than that of the down signal. |
