| 摘要 |
PURPOSE:To make countermeasures for a power failure of the trouble and defect of a terminal station unnecessary and to improve transmission efficiency by dividing an optical loop into plural sections, causing the total number of the terminal stations, which are respectively coupled to each section, to be <= the number of the sections and providing a reproducing and repeating means in a partitioning spot. CONSTITUTION:Repeating stations 22 and 23 divides the optical loop, which defines a loop control station 21 as a starting point and an ending point, into sections A-C and terminal stations 24-26, 27-29 and 30-32 to be <= the number of all the sections are coupled to the respective sections A-C. A requesting signal train goes to be the optical signal of a wavelength lambda1 and is sent to the optical loop by optical fibers a1-a3. Then, one part of the signal train is branched in each optical branching device and sent to the connected terminal station. A responding signal from the terminal station goes to be the optical signal of a wavelength lambda2 and it is loaded on an optical fiber 1. The optical signals of the wavelengths lambda1 and lambda2 to be transmitted through the optical fibers a1-a3 are received by the repeating stations 22 and 23 or by an optical receiver, to which the loop control station 21 is correspondent, in each section. Thus, it is not necessary to obtain reproducing and repeating function in the respective terminal stations 24-32. |
