Standard (NRZ 1 x 40 Gb/s, 210 km) and polarization multiplex (CS-RZ, 2 x 40 Gb/s, 212 km) transmissions with PMD compensation

A single-waveplate polarization scrambler at the transmitter (TX) generates pulse arrival time fluctuations in the presence of polarization-mode dispersion. These were detected with a 680-fs sensitivity in the receiver clock recovery phase-locked loop, thereby enabling a polarization-mode dispersion (PMD) compensated 210-km nonreturn-to-zero transmission. For polarization division multiplex, polarizations were scrambled by an interchannel phase modulation which enabled PMD-compensated CS-RZ 212-km transmission.