Systems and methods for polarization mode dispersion mitigation

A polarization mode dispersion (PMD) mitigation apparatus comprising:

• an optical detector optically coupled to an optical line, where the optical detector is operable to receive a portion of an optical input signal having a clock frequency (fc) and convert it into an electrical signal;
• a clock recovery unit electrically coupled to the optical detector, where the clock recovery unit is operable to extract a clock signal from the electrical signal;
• a first combiner electrically coupled to the clock recovery unit and to the optical detector, where the first combiner is operable to mix the extracted clock signal with the electrical signal;
• a first lowpass filter electrically coupled to the combiner, where the first lowpass filter is operable to receive an output signal from the first combiner and produce a filtered electrical signal;
• and
• a first radio-frequency (RF) detector electrically coupled to the first lowpass filter, where the first RF detector is operable to measure an intensity of the filtered electrical signal at fc.

A polarization mode dispersion (PMD) mitigation device comprising:

• a fiber circulator optically coupled to an optical line;
• a first collimator optically coupled to the fiber circulator;
• a polarization controller optically coupled to the first collimator;
• a first birefringent crystal optically coupled to the polarization controller;
• a tunable λ/2 plate optically coupled to the first birefringent crystal;
• a second birefringent crystal optically coupled to the tunable λ/2 plate;
• and
• a reflective surface optically coupled to the second birefringence crystal.