  Investigation of internal polarization dynamics of vector
dissipative-soliton-resonance (DSR) pulses in a mode-locked fiber laser is
presented. Stable vector DSR pulses are experimentally ob- served. Using a
waveplate-analyzer configuration, we find that polarization is not uniform
across a resonant dissipative soliton. Specifically, although the central plane
wave of the resonant dissi- pative soliton acquires nearly a fixed
polarization, the fronts feature polarization states that are different and
spatially varying. This distinct polarizaiton distribution is maintained while
the whole soliton structrue extends with varying gain conditions. Numerical
simulation further confirms the experimental observations.
