There are provided a plurality of optical adjusting sections, a wavelength-multiplexing
section, and a control section. The plurality of optical adjusting sections, which
are provided for respective wavelength bands, amplifies light beams in the respective
wavelength bands. The wavelength-multiplexing section wavelength-multiplexes amplified
light beams in the respective wavelength bands. The control section controls the
outputs of the respective optical amplifying sections so that optical powers of
the respective wavelength bands will become approximately identical at a predetermined
point when wavelength-multiplexed light of the light beams in the respective wavelength
bands travels to the predetermined point. This configuration makes it possible
to eliminate optical power deviations between wavelength bands that would otherwise
occur when an optical signal of a plurality of wavelength bands is transmitted,
and to thereby make optical SNRs uniform.
