| 摘要 |
PURPOSE:To enable on-line monitor by passing a signal for data transmission, signal for control and signal for monitor through the same optical fiber while multiplexing wavelengths and returning the signal for control at the time of a teat. CONSTITUTION:The optical signal for data transmission with a wavelength lambda1 and the optical signal for return control with a wavelength lambda2 are sent from a monitor station trough an optical fiber transmission line while multiplexing the wave lengths. The optical signal with the wavelength lambda2 is separated by an optical synthesizing/branching filter 1, and an electric/optical converter 11 outputs an optical signal with a wavelength lambda3. A band pass filter 5 extracts only a frequency component allocated to its own repeater. A control signal detecting circuit 6 decides a state to be controlled from the output of the filter 5 and sends control signals to optical switches 7-9. The optical switch 9 outputs the optical signal with the wavelength lambda3 from the optical switch 8 at the time of control and output the optical with the wavelength lambda3 from an optical synthesizing/branching filter 12 at the time of non-control. This optical signal with the wavelength lambda3 is synthesized by the optical synthesizing/branching filter 1 and outputted to a monitor station side optical fiber transmission line. |
