1.6-b/s/Hz 160-Gb/s 230-km RZ-DQPSK polarization multiplex transmission with tunable dispersion compensation

A 160-Gb/s (4/spl times/40 Gb/s) return-to-zero differential quadrature phase-shift keying polarization-division multiplex transmission is demonstrated with Q>15.6 dB in one of eight 100-GHz-spaced wavelength-division-multiplex channels after 230 km of fiber. Residual chromatic dispersion (CD) is equalized by a thermally tunable CD compensator for the 192.5-THz channel. Polarizations, in-phase and quadrature data channels are demultiplexed using a LiNbO/sub 3/-based automatic polarization control and a 1-bit interferometer, respectively.