Direct modulation 565 Mb/s DPSK experiment with 62.3 dB loss span and endless polarization control

Optical DPSK at 565 Mb/s is performed by direct modulation of a narrow-linewidth 1.5- mu m SL-QW-DFB (strain layer-quantum well-distributed feedback) transmitter laser. The bipolar RZ drive signal has no DC component which allows penalty-free transmission of 2/sup 23/-1 bit patterns. The heterodyne receiver contains an endless polarization controller with12 rad/s tracking speed, depending on the tolerable intensity loss. A loss span of 62.3 dB is achieved,without degradation due to stimulated Brillouin scattering.>