| CPC H04J 14/0221 (2013.01) [H04B 10/564 (2013.01)] | 14 Claims |

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1. A transmission apparatus comprising:
a signal power detector configured to detect signal power of a wavelength-multiplexed optical signal to be transmitted to a transmission line;
a variable optical attenuator configured to attenuate the wavelength-multiplexed optical signal; and
a processor configured to control an attenuation amount of the variable optical attenuator according to the signal power and whether a Raman amplifier in which pumping light is inputted to the transmission line exists.
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