Patent ID: 6845109

Claim:
A method for correcting a shift of an output wavelength of a light source, the shift of the output wavelength being generated by adjustment of a drive current in the light source used in an optical communication system, comprising the steps of: 1) setting an initial drive current and an initial drive temperature of the light source according to an output light intensity and an output wavelength which are previously set; 2) obtaining a correlation between a drive current and an output wavelength of the light source at the initial drive temperature, and calculating coefficients “a”, “b”, “c” and “d” of the following Equation [1] using the correlation between the drive current and the output wavelength, where x is the drive current and y is the output wavelength; y=ax 3 +bx 2 +cx+d [1] 3) obtaining a correlation between a drive temperature and the output wavelength of the light source at the initial drive current, and calculating coefficients “e” and “f” of the following Equation [2] using the correlation between the drive temperature and the output wavelength, where y is the output wavelength and z is the drive temperature; and y=ez+f [2] 4) calculating an output wavelength shifted by a reset drive current through the Equation [1] if the drive current is reset, calculating a wavelength difference between the set output wavelength based on the initial drive current and the shifted output wavelength, and calculating a reset drive temperature according to the wavelength difference using the initial drive temperature and the coefficient “e” of the Equation [2], thus resetting the drive temperature.