| 摘要 |
PROBLEM TO BE SOLVED: To provide a technique for detecting the optical level, of an optical signal to be received, easily and accurately in the WDM system by digital coherent.SOLUTION: The transponder of a transmitter for transmitting wavelength division multiplex optical signals to a plurality of transmission lines having different transmission direction includes a light source emitting light having the wavelength of an optical signal to be received, a determination unit for determining the state of the transmission line by detecting the optical level of an optical signal to be received, from the wavelength division multiplex optical signal transmitted on the transmission line, by using the light emitted from the light source, a switching unit for selecting one transmission line as an active system on the basis of the determination results and switching to that transmission line, and a reception unit for receiving the optical signal to be received, from the wavelength division multiplex optical signal transmitted on one transmission line while separating. |
