Patent ID: 8032025

Claim:
A system for providing optical communication based on polarization division multiplexing (PDM), comprising: an optical input port to receive an optical signal that carries first and second data channels on first and second orthogonal initial optical polarizations, respectively, based on PDM, wherein a radio frequency (RF) tone signal is modulated onto light in the first initial optical polarization along with the first data channel while light in the second initial optical polarization is free of the RF tone signal; a polarizing beam combiner (PBC) connected downstream from the optical input port to split light from the optical input port into a first beam in a first polarization and a second beam in a second polarization that is orthogonal to the first polarization; a first optical detector to detect the first beam and to extract the first data channel; a second optical detector to detect the second beam and to extract the second data channel; a polarization controller coupled between the optical input port and the PBC to control optical polarization of received light, which is directed from the optical input port, to produce output light propagating towards the PBC; an optical splitter coupled between the optical input port and the PBC to split a portion of received light, which is directed from the optical input port, as a probe beam and transmit the remainder of the received light towards the PBC for detection by the first and second optical detectors; a polarization detection unit that receives the probe beam from the optical splitter and measures a polarization state of light received at the optical splitter and a power level of light associated with the RF tone signal; and a feedback control unit in communication with the polarization detection unit to produce a feedback control signal to the polarization controller to adjust the optical polarization of the light at the optical splitter to optimize a separation of the first and second data channels for optimal detection by, respectively, the first and second optical detectors.