  We address the issue of dephasing effects in flying polarization qubits
propagating through optical fiber by using the method of dynamical decoupling.
The control pulses are implemented with half waveplates suitably placed along
the realistic lengths of the single mode optical fiber. The effects of the
finite widths of the waveplates on the polarization rotation are modeled using
tailored refractive index profiles inside the waveplates. We show that
dynamical decoupling is effective in preserving the input qubit state with the
fidelity close to one when the polarization qubit is subject to the random
birefringent noise in the fiber, as well the rotational imperfections
(flip-angle errors) due to the finite width of the waveplates.
