| 摘要 |
PURPOSE:To raise reliability of an optical repeater, by constituting so that another light emission element can be operated when a light emission element has been deteriorated. CONSTITUTION:When an input signal is inputted from a teminal 15 and is inputted to the base of a transistor (TR)22 through contacts (a)-(b) of a changeover switch 18, a light emission element 21 is operated and is inputted to a branching circuit 25. A part of optical signal of the circuit 25 is converted to an electric signal by an optical signal/ electric signal converting circuit 23, and its converted output is inputted to a checking circuit 19. When an operation of the element 21 is normal, positive voltage is outputted to an output of the circuit 19, and a changeover switch driving circuit 17 holds a state as it is. If an output of the circuit 23 has become lower than a prescribed value due to deterioration of the element 21, the output of the circuit 19 becomes negative voltage, the circut 17 is operated by its negative voltage, and the switch 18 is changed over to the contacts (a)-(c) from (a)-(b). Subsequently, the input signal is inputted to the base of TR27, and a light emission element 26 is operated. An optical signal of the element 26 passes through a light branching circuit 28, a part of its signal is converted to an electric signal by an optical signal/electric signal converting circuit 24, and is inputted to a checking circuit 20. |
