Using differential detection, we perform polarization-multiplexing 160-Gb/s optical non-return-to-zero (NRZ) differential quadrature phase shift keying (DQPSK) signal transmission over 100-km standard single mode fiber at a bit error rate (BER) of less than 10-9. The enabling technology includes clock recovery, fine dispersion compensation, and polarization tracking for de-multiplexing. Furthermore, a hybrid clock recovery scheme is proposed. The scheme is realized with ordinary devices using an optoelectrical modulator to down-convert the clock frequency and a phase-locked loop for filtering, which can provide an indication signal that simultaneously monitors residual dispersion and tracking polarization.