Slope control of gain wavelength of raman amplification

A wavelength division multiplexing optical communication system in which an optical sender and an optical receiver are interconnected via an optical transmission path, and wavelength division multiplexed signal light is transmitted through said optical transmission path to cause wavelength characteristics of optical transmission powers, comprising:

• a Raman amplification generating means including:
• a pump light generating part for generating Raman pump lights of a plurality of wavelength band sets corresponding to linear wavelength characteristics of optical transmission powers;
• a Raman amplifying medium forming at least a part of said optical transmission path;
• and a pump light supplying part for supplying said Raman pump lights of said plurality of wavelength band sets to said Raman amplifying medium;
• so as to generate Raman amplification having gain wavelength characteristics capable of compensating said linear wavelength characteristics of optical transmission powers, for wavelength division multiplexed signal light propagated through said Raman amplifying medium, said gain wavelength characteristics of Raman amplification being such that gain wavelength characteristics corresponding to Raman pump lights of at least one set of said wavelength band sets among said Raman pump lights of the plurality of said wavelength band sets has slope characteristics in linearly opposite directions in a signal light band;
• a wavelength characteristic monitoring means for monitoring wavelength characteristics of optical transmission powers, for wavelength division multiplexed signal light passed through said Raman amplifying medium;
• and
• a Raman amplification controlling means for adjusting proportions of said Raman pump lights of at least one set of said wavelength band sets at said pump light generating part based on a monitoring result of said wavelength characteristic monitoring means, to thereby control the gain wavelength characteristics of Raman amplification such that said wavelength characteristics of optical transmission powers are flattened.

An optical amplifier connected to an optical transmission path causing wavelength characteristics of optical transmission powers in wavelength division multiplexed signal light, so as to amplify the wavelength division multiplexed signal light to be transmitted through said optical transmission path, the optical amplifier comprising:

• a Raman amplification generating means including:
• a pump light generating part for generating Raman pump lights of a plurality of wavelength band sets corresponding to linear wavelength characteristics of optical transmission powers;
• a Raman amplifying medium to be connected to said optical transmission path;
• and a pump light supplying part for supplying said Raman pump lights of the plurality of wavelength band sets to said Raman amplifying medium;
• so as to generate Raman amplification having gain wavelength characteristics capable of compensating said linear wavelength characteristics of optical transmission powers, for wavelength division multiplexed signal light propagated through said Raman amplifying medium;
• said gain wavelength characteristics of Raman amplification being such that gain wavelength characteristics corresponding to Raman pump lights of at least one set of said wavelength band sets among said Raman pump lights of the plurality of said wavelength band sets has slope characteristics in linearly opposite directions in a signal light band;
• a wavelength characteristic monitoring means for monitoring wavelength characteristics of optical transmission powers, for wavelength division multiplexed signal light passed through said Raman amplifying medium;
• and
• a Raman amplification controlling means for adjusting proportions of said Raman pump lights of at least one set of said wavelength band sets at said pump light generating part based on a monitoring result of said wavelength characteristic monitoring means, to thereby control the gain wavelength characteristics of Raman amplification such that said wavelength characteristics of optical transmission powers are flattened.

A method for controlling wavelength characteristics of optical transmission powers, the method comprising:

• supplying Raman pump lights of a plurality of wavelength band sets corresponding to linear wavelength characteristics of optical transmission powers, to a Raman amplifying medium, so as to generate Raman amplification having gain wavelength characteristics capable of compensating said linear wavelength characteristics of optical transmission powers for wavelength division multiplexed signal light propagated through said Raman amplifying medium, wherein at least one set of said wavelength band sets among said Raman pump lights has slope characteristics in linearly opposite directions in a signal light band;
• monitoring said linear wavelength characteristics of optical transmission powers for wavelength division multiplexed signal light propagated through said Raman amplifying medium;
• and
• adjusting said Raman pump lights of at least one set of said wavelength band sets based on a result of said linear wavelength characteristic monitoring step, to thereby control the gain wavelength characteristics of Raman amplification such that said wavelength characteristics of optical transmission powers are flattened.

A wavelength division multiplexing optical communication system comprising:

• a Raman amplification generator device including:
• a pump light generating part generating Raman pump lights of a plurality of wavelength band sets corresponding to linear wavelength characteristics of optical transmission powers;
• a Raman amplifying device forming at least a part of said optical transmission path;
• and a pump light supplying part supplying said Raman pump lights to said Raman amplifying medium;
• so as to generate Raman amplification having gain wavelength characteristics capable of compensating said linear wavelength characteristics of optical transmission powers, for wavelength division multiplexed signal light propagated through said Raman amplifying medium, wherein at least one set of said wavelength band sets has slope characteristics in linearly opposite directions in a signal light band;
• a wavelength characteristic monitoring device monitoring wavelength characteristics of optical transmission powers, for wavelength division multiplexed signal light propagated through said Raman amplifying medium;
• and
• a Raman amplification controlling device adjusting said Raman pump lights of at least one set of wavelength band sets at said pump light generating part based on a monitoring result of said wavelength characteristic monitoring device, to thereby control the gain wavelength characteristics of Raman amplification such that said wavelength characteristics of optical transmission powers are flattened.