Apparatus for compensating polarization mode dispersion

An apparatus for compensating a polarization mode dispersion (PMD), the apparatus comprising:

• a polarization adjuster for adjusting polarization states of an optical beam inputted through a transmission optical link;
• a polarization beam splitter for splitting principal states of polarization of the adjusted optical beam to a first polarization and a second polarization and transmitting a first polarization through a first routine and the second polarization to a second routine;
• a first photo detector for converting the first polarization into an electric signal;
• an optical tap for tapping a part of the second polarization and passing the remained part of the second polarization;
• a second photo detector for converting the remained second polarization into an electric signal;
• a third photo detector for converting the tapped signal into an electric signal;
• a first band pass filter for filtering the electric signal;
• a first radio frequency detector for detecting electric power of the filtered signal;
• a polarization adjuster controller for controlling the polarization adjuster based on the electric power detected from the first radio frequency detector;
• an electric delay line for providing a time delay in the electric signal converted by the first photo detector;
• an electric combiner for combining the time-delayed signal from the EDL and the electric signal from the second photo detector;
• an electric divider for tapping the combined signal from the electric combiner;
• a second band pass filter for filtering a specific frequency of the tapped signal from the electric divider;
• a second radio frequency detector for detecting electric power of the band passed signal from the second band pass filer;
• and
• an EDL controller for controlling the electric delay line based on the detected signal from the second radio frequency detector.