  In this paper, we demonstrate the polarization-multiplexed system capable of
generating two stable optical frequency combs with tunable frequency
differences and a large extinction ratio. Also, the polarization dynamics of a
dual-frequency comb generated from a single mode-locked Er-doped fiber laser
are experimentally studied. The obtained results will extend the application to
areas such as polarization spectroscopy and dual-comb-based polarimetry.
