Optical transmission apparatus and control method of optical transmission apparatus

An optical transmission apparatus comprising:

• multiplexing circuit is configured to multiplex a plurality of subcarrier signals for performing optical wavelength multiplexing communication into a wavelength group signal;
• output circuit is configured to outputting the multiplexed wavelength group signal to an optical transmission line;
• pre-multiplexing level correction circuit is configured to correct a level deviation between the subcarrier signals before the multiplexing based on an optical level of the wavelength group signal in the output circuit;
• and
• post-multiplexing level correction circuit is configured to correct a level deviation of the wavelength group signal after the multiplexing including the corrected subcarrier signals based on the optical level of the wavelength group signal in the output circuit.