Patent ID: 7460789

Claim:
A method of controlling an optical transmission system for compensating for chromatic dispersion that is caused when an optical signal is transmitted, comprising the steps of: determining a target value for a nonlinear phase shift, which is an indication of a self-phase modulation caused by a path through which said optical signal is transmitted, to have a maximum residual dispersion tolerance; determining at least one of the input power applied to a transmission path connected to a node providing said path and the input power applied to a dispersion compensation module providing said path, in order to equalize said nonlinear phase shift to the target value; and controlling said optical transmission system based on the determined input power; wherein if a loss of each of spans of said path differs from span to span, the average input power applied to the transmission path is determined from a nonlinear phase shift per span, which is produced by dividing said target value by the number of the spans, and half of a power variation from an average span loss is assigned to a power variation of the average input power applied to the transmission path thereby to determine the input power applied to the transmission path of the span.