Patent ID: 8775135

Claim:
A design method for compensating chromatic dispersion, the design method comprising: calculating a calculated compensation amount of a dispersion compensation module arranged on each of a plurality of wavelength paths in such a way that a residual chromatic dispersion value of each of the wavelength paths which transmits an optical signal between an initial node and a final node satisfies a tolerance condition given in accordance with a priority given to each of the wavelength paths; and deciding a decision value to be applied as the compensation amount of the dispersion compensation module based on the calculated compensation amount based on a plurality of candidate values each being prepared in advance as a candidate for the compensation amount of the dispersion compensation module, wherein the decision value is decided based on the plural candidate values in such a way that a residual chromatic dispersion value of each of the wavelength paths satisfies a specific condition, the specific condition is such that: (i) a summation of an error between a residual chromatic dispersion value of a first wavelength path included in the plural wavelength paths and a residual chromatic dispersion target value corresponding to the first wavelength path is minimized, the first wavelength path being assigned a highest priority; and that (ii) a residual chromatic dispersion value of a second wavelength path being lower in priority than the first wavelength path remains within a tolerable residual chromatic dispersion range corresponding to the second wavelength path.