| 摘要 |
PURPOSE:To control an optical signal sent and received through an optical fiber while not modifying the optical signal by allowing an optical switch to use a 2-input 2-output matrix switch of direction coupling type in an optical loop node switch. CONSTITUTION:With optical switches 2A, 2B and 2C set in the bar state, when the optical switch 2A receives an optical signal sent from an adjacent node counter clockwise, the switch 2A sends the optical signal to an optical signal reception circuit 4A. Then the optical signal inputted to the switch 1 is sent again to a succeeding node through the optical fiber 10. Similarly with optical switches 2F, 2E and 2D set in the bar state, the optical signal sent clockwise is subject similarly to transmission control in the inside of the switch 1 as the signal above. When the optical signal is not sent from a node provided with the switch 1, the optical signal received through the optical fiber is sent to a destination node without being converted into the electric signal at the receiving node. |
