| 摘要 |
<p>An optical amplifier multiplexes pump lights, having different wavelengths output from a plurality of pump light sources, on a wavelength-division multiplexed signal light propagating through a transmission path to provide Raman amplification. The optical amplifier includes an intensity modulator that modulates the intensity of pump light output from a pump light source, out of the pump light sources, at a predetermined frequency. The optical amplifier also includes a gain modulation signal detector that converts a part of the wavelength-division multiplexed signal light Raman-amplified to electrical signals, and extracts a gain modulation signal having a component of the frequency from the electrical signals converted. The optical amplifier further includes a controller that controls only the intensity of the pump light, output from a pump light source, of which intensity is modulated at the frequency to control Raman amplification gain so that an amplitude of the gain modulation signal extracted within a predetermined period becomes a predetermined value. <IMAGE></p> |
