Optical transmission apparatus and wavelength control method

A wavelength control method executed by an optical transmission apparatus including a first transmitter, a second transmitter, and a processor, the wavelength control method comprising:

• among a first wavelength band of a first optical signal, a second wavelength band located next to the first wavelength band of a second optical signal, a third wavelength band located next to the second wavelength band of a third optical signal, a fourth wavelength band located next to the third wavelength band of a fourth optical signal, selecting the third wavelength band by the processor, wherein the third optical signal is different from the first optical signal and the fourth optical signal is different from the second optical signal,
• controlling the first wavelength band, the second wavelength band, and the fourth wavelength band based on the reference band,
• transmitting by the first transmitter the first optical signal having the first wavelength band controlled by the processor, and the second optical signal having the second wavelength band controlled by the processor, and
• transmitting by the second transmitter the third optical signal having the third wavelength band controlled by the processor, and the fourth optical signal having the fourth wavelength band controlled by the processor.