A system for detecting dispersion in an incoming optical signal centered about a channel center frequency. The system includes a splitter unit for separating the incoming signal into first and second groups of signals. The system further includes a first compensation region adapted to apply a desired positive dispersion characteristic to a signal in the first group and a second compensation region adapted to apply a desired negative dispersion characteristics to a signal in the second group. The splitter also includes a receiver unit connected to the first and second compensation regions, and adapted to compare the received signals and to detect the dispersion in the incoming optical signal on the basis of the comparison. The system can be selectively balanced at different optical frequencies by varying the amount of dispersion applied by the first and second compensation regions. It is thus possible to balance the system at a given channel center frequency such measurement of a minimal resultant dispersion in the receiver unit is indicative of the incoming optical signal being dispersion-free at that frequency.