43 Gb/s DQPSK pre-equalization employing 6-bit, 43GS/s DAC integrated LSI for cascaded ROADM filtering

Electronic pre-equalization for 43 Gb/s DQPSK has been demonstrated for the first time. Waveform distortion caused by bandwidth narrowing to 18.1 GHz by cascaded 10 Gb/s ROADMs has been adequately pre-equalized by a SiGe-BiCMOS LSI with 6-bit, 43 GS/s digital-to-analog converters.