Patent ID: 7068945

Claim:
An optical amplifying and repeating method for connecting between a first station and a second station with a first optical transmission line and a second optical transmission line, wherein: said first optical transmission line transmits an optical signal in a first direction from the first station toward the second station and includes at least one first optical amplifier on the way; and said second optical transmission line transmits an optical signal in a second direction from the second station toward the first station and includes at least one second optical amplifier on the way, said method comprising: taking backscattering light of a first wavelength traveling in the first direction of the first optical transmission line immediately after the first optical amplifier, and coupling the same in such a manner that said backscattering light may travel in the second direction of the second optical transmission line; taking a second wavelength traveling in the first direction of the first optical transmission line and coupling the same in such a manner that the second wavelength may travel in the first direction of the second optical transmission line; taking backscattering light of the first wavelength traveling in the second direction of the second optical transmission line immediately after the second optical amplifier, and coupling the same in such a manner that said backscattering light may travel in the first direction of the first optical transmission line; and taking the second wavelength traveling in the second direction of the second optical transmission line and coupling the same in such a manner that the second wavelength may travel in the second direction of the first optical transmission line.