Precision measurement scheme for beat-length of polarization maintain optical fiber

A precision measurement scheme for beat-length of polarization maintain optical fiber was proposed based on optical coherence domain polarimetry, and the beat-length of polarization maintain optical fiber with different structures and sizes was measured. The principle of optical coherence domain polarimetry was demonstrated and the beat-length measurement equation was derived. A measurement system was setup by modifying the Michelson interferometer and precision measurement was achieved with the modulation and demodulation technology. The error analysis shows that the measuring error is less than 0.01 mm. The performance including accuracy and repetition was investigated with this system, the beat-lengths of 8 types of polarization maintain optical fibers with different structures and sizes were measured, the result shows that the accuracy and repetition of beat-length measurement are both better than 0.01 mm.