  We report on the experimental observation of incoherently coupled dark vector
soliton trapping in a fiber laser. Dark vector solitons along the two
orthogonal polarization directions though with large difference in central
frequency, energy and darkness could be still synchronously trapped as a group
velocity locked dark vector soliton in virtue of the incoherent interactions.
Our numerical simulation could well rebirth the experimental observations and
confirm the existence of incoherently coupled dark vector soliton under certain
conditions.
