| 摘要 |
PURPOSE:To allow a corresponding optical reception panel to surely raise an alarm representing a state of an optical output interruption even when one optical transmission panel reaches the state in the wavelength multiplex communication system. CONSTITUTION:A 1st optical transmission panel 111 provides an output of an optical digital signal string whose wavelength is lambda1 as a light intensity change whose frequency is f1 and a 2nd optical transmission panel 112 provides an output of an optical digital signal string whose wavelength is lambda2 as a light intensity change whose frequency is f2. They are multiplexed by an optical multiplexer 13 and distributed by an optical distributer 16 at a reception end of a transmission line. After the signal is distributed, the optical signals whose specific wavelengths lambda1, lambda2 are extracted by 1st and 2nd optical band pass filters 171, 172 and inputted to a 1st optical reception panel 191 or a 2nd optical reception panel 192. Each of the optical reception panels 191, 192 is provided with a band pass filter 26 passing a relevant frequency f1 or f2 and an alarm is raised when no passing is detected. |
