System and method for stabalization of multi-path optical interferometers

A system for phase extraction of a multi-path interferometer, comprising:

• a light source, said light source generating a coherence length longer than an arm length difference of the multi-path interferometer;
• a polarization multiplexing unit connected to the multi-path interferometer;
• a detection unit;
• and
• a signal processing unit at the output of the multi-path interferometer;
• wherein said polarization multiplexing unit splits a reference signal generated by said light source into a frequency shifted reference signal and an unshifted reference signal, recombines said frequency shifted reference signal and said unshifted reference signal into a polarization- and frequency-multiplexed reference signal, and feeds the polarization- and frequency-multiplexed reference signal to the multi-path interferometer;
• said detection unit detecting frequency-shifted and unshifted output signals of the multi-path interferometer;
• and said signal processing unit determines the interferometer phase from the signals detected by the detection unit.