Patent ID: 8554071

Claim:
An optical transmission apparatus comprising: an amplifier to receive and amplify wavelength-division-multiplexed signal light; a first output port to select a wavelength from the wavelength-division-multiplexed signal light amplified by the amplifier and output signal light with the selected wavelength to an operation line, which is one of a plurality of optical transmission lines; a second output port to output multiplexed light obtained by multiplexing any one of first spontaneous emission light and second spontaneous emission light to a preliminary line, which is another one of the plurality of optical transmission lines, the first spontaneous emission light and the second spontaneous emission light being parts of spontaneous emission light generated by the amplifier, the first spontaneous emission light being in a wavelength range that is not selected by the first output port, and the second spontaneous emission light being in a wavelength range other than a wavelength range of the wavelength-division-multiplexed signal light; and a judger to judge a continuity state of the operation line by using the signal light output to the operation line by the first output port and judge a continuity state of the preliminary line by using the multiplexed light output to the preliminary line by the second output port.