Research

By combining two optical frequency combs with equal repetition rates, unequal offset frequencies, and orthogonal polarization directions, a synthetic frequency comb with a time-varying polarization state can be obtained, and the modulation speed of the polarization state can be adjusted by the difference in offset frequencies. If optical frequency comb with a different repetition rate is used to sample the synthetic optical frequency comb with a time-varying polarization state, the polarization state information of the synthetic optical frequency can be determined. Since the polarization state depends on the phase difference between the two orthogonally polarized beams, and the phase difference is affected by the optical path difference thus contains noise, the impact of the optical path difference can be compensated by controlling the magnitude of the offset frequency through FM feedback, thereby obtaining a stable polarization sequence