| 摘要 |
PURPOSE:To make the transmission capacity of a connection part the same as that of an optical loop type local area network to be connected, to make the size of the connection part small and to attain economy by connecting terminals of 1st and 2nd optical switches to an optical loop and switching an optical switch when the interruption of input light at the terminal is detected. CONSTITUTION:The 1st terminal 01 of the 1st and 2nd optical switches 5, 6 is connected to a 1st optical loop A, a common terminal C of the 1st optical switch 5 is connected to an input terminal of a photoelectric conversion circuit 1, a common terminal C of the 2nd optical switch 6 is connected to an output terminal of an electrooptic conversion circuit 2 and the 2nd terminal 02 of the 1st and 2nd optical switches is connected to a 2nd optical loop B. When the interruption of input light at the 1st terminal 01 of the 1st and 2nd optical switches 5, 6 is detected, control circuits 60, 61 are provided to connect the 2nd terminal 02 and the common terminal C. Thus, the transmission capacity of the connection section is made equal to the transmission capacity of the optical loop type local area network to be connected and the connection section is made small in size the economy is attained. |
