Arrangement for automatically adjusting for accumulated chromatic dispersion in a fiber optic transmission system

An arrangement for automatically measuring accumulated chromatic dispersion in an optical transmission system, the arrangement comprising

• a splitter for dividing a portion of a received optical signal into essentially equal first and second optical signal components, each component exhibiting an amount of accumulated chromatic dispersion;
• a first optical delay unit for introducing an amount of positive chromatic dispersion into the first optical signal;
• a second optical delay unit for introducing an amount of negative chromatic dispersion into the second optical signal, the amount of negative chromatic dispersion being equal in magnitude and opposite in sign to the amount of positive chromatic dispersion;
• a first nonlinear optical detector responsive to the output from the first optical delay unit;
• a second nonlinear optical detector responsive to the output from the second optical delay unit;
• and
• a subtracting arrangement coupled to the outputs from the first and second nonlinear optical detectors for generating a difference signal, defined as an error signal, indicative of the magnitude and sign of the accumulated chromatic dispersion present in the optical signal propagating through the transmission system.