Patent ID: 6061173
Filing Date: 2000-05-09
Classification: H01S,H04B,H04J

Abstract:
A method for amplifying a wavelength-division-multiplexed optical signal composed of an optical signal of 1.535-.mu.m-band wavelength and an optical signal composed of an optical signal of 1.55-.mu.m-band wavelength, comprising the steps of:inputting the wavelength-division-multiplexed optical signal to an erbium-doped optical fiber;amplifying said input wavelength-division-multiplexed optical signal by providing excitation beams of 0.98-.mu.m-band wavelength and 1.48-.mu.m-band wavelength into the erbium-doped optical fiber;monitoring each component level output from said optical fiber of the optical signal of 1.535-.mu.m-band wavelength and the optical signal of 1.55-.mu.m-band wavelength of the amplified wavelength-division-multiplexed optical signal;comparing the levels of two components of the optical signal of 1.535-.mu.m-band wavelength and the optical signal of 1.55-.mu.m-band wavelength;controlling the excitation beams of 0.98-.mu.m-band wavelength and 1.48-.mu.m-band wavelength by increasing either one of said excitation beams to equalize the two component levels relative to each other by increasing the lower level of one component to the higher level of the other component.