Patent ID: 7212333

Claim:
An optical node having a plurality of receiving ports of wavelength-division-multiplex optical signals requiring Raman amplification for low-noise characteristic, comprising: an excitation light source unit for Raman amplification, generating Raman excitation light of a plurality of wavelengths; a control unit outputting the generated Raman excitation light of the plurality of wavelengths, wavelength by wavelength on a time division basis; and a Raman amplifier distributing and feeding the Raman excitation light of the plurality of wavelengths, wavelength by wavelength on a time division basis, in the opposite direction to the signal light transmission direction, wherein in each receiving port, a period of the Raman excitation light being output wavelength by wavelength on a time division basis is set shorter than a signal light response time in the Raman amplifier to the Raman excitation light, the excitation light source unit for Raman amplification includes a plurality of Raman excitation light sources corresponding to required frequencies, and the control unit includes, a plurality of switches each corresponding to each of the plurality of Raman excitation light sources, switching and supplying the outputs of the Raman excitation light sources to the plurality of receiving ports, a switch controller controlling the plurality of switches, and a controller controlling light emission from each of the plurality of Raman excitation light sources.