Patent ID: 8078065

Claim:
An apparatus, comprising an optical receiver adapted to recover data carried by a modulated optical carrier, wherein the optical receiver comprises: an optical detector adapted to produce a sequence of vector pairs having first and second digital vectors, each first digital vector being indicative of a complex value of a first polarization component of the modulated optical carrier at a corresponding sampling time, and each second digital vector being indicative of a complex value of a different second polarization component of the modulated optical carrier at the sampling time; and a digital processor being connected to receive the sequence of said vector pairs and being adapted to perform a rotation on a pair from said sequence in a manner that tends to compensate for polarization rotation produced during transmission of the modulated optical carrier from an optical transmitter thereof to the optical receiver, the digital processor being configured to recover said data from vectors resulting from the performed rotation, wherein the digital processor is adapted to recursively update an angle of the rotation by an amount proportional to a value of energy difference between vectors of a vector pair produced by a previous rotation of a previous vector pair having the corresponding first and second vectors.