| 摘要 |
PURPOSE:To eliminate repeating actions in an electric system in respective nodes and to evade the instantaneous interruption of a communication network caused by the variation of light levels by controlling a by-pass light and a branching light in the same level and inserting them into assigned time slots in respective general nodes. CONSTITUTION:A titled circuit has a light coupler 1 which divides an inputted light into the by-pass light and the branching light in a specified ratio, an insertion circuit 2 which controlls the branching light to be equal to the level of the by-pass light in a specified ratio and an output means 3 for outputting the controlled branching light. The light beam inputted in an optical access circuit is divided into the by-pass light and the branching light in the specified ratio in the light coupler 1 and the branching light is controlled to be equal to the level of the by-pass light based on the specified division ratio in the light coupler 1 by the insersion circuit 2. And the controlled branching light is outputted to a ring from the output means 3. Thus the optical access circuit can be obtained, in which the fault of the respective nodes in the ring-shaped light communication network does not stop the communication of the whole communication network. |
