In-service optical dispersion determining system and method

An optical receiving component comprising:

• a splitter-delayer-combiner that:
• splits a first optical signal into a first polarization component and a second polarization component;
• introduces a relative time delay τ between the first polarization component and the second polarization component;
• and
• combines the relatively delayed first and second polarization components to generate a combined optical signal;
• a tunable dispersion compensation module (TDCM) that applies each of a plurality of dispersion compensation values such that dispersion of at least one of:
• a) the first polarization component of the combined optical signal;
• and
• b) the second polarization component of the combined optical signal,
• is affected by each dispersion compensation value;
• a power detector that detects power of the combined optical signal while the TDCM applies the plurality of dispersion compensation values;
• and
• a controller that controls the TDCM and determines a dispersion compensation value of the plurality of dispersion compensation values that results in a minimum detected power of the combined optical signal.

A method comprising the steps of:

• splitting a first optical signal into a first polarization component and a second polarization component;
• introducing a relative variable delay time τvar between the first polarization component and the second polarization component;
• combining the relatively delayed first and second polarization components to generate a combined optical signal;
• determining power of the combined optical signal while applying a plurality of dispersion compensation values to the combined optical signal;
• adjusting the relative variable delay time τvar until the power of the combined optical signal is substantially equal for each of the plurality of dispersion compensation values;
• and
• determining that an amount of PMD (polarization mode dispersion) in the first optical signal resulting in a time delay τpmd between the first polarization component and the second polarization component of the combined optical signal is equal to the relative variable delay time τvar for which the power of the combined optical signal is substantially equal for each of the plurality of dispersion compensation values.