Directly Modulated Laser Driven by Low-Bandwidth Duobinary Signals

We report on the generation of 10-Gb/s nonreturn-to-zero signals using a directly modulated laser driven by 9B/10B line-coded, 3.5-GHz-bandwidth duobinary signals. The ternary frequency-modulated signals from the laser are converted into binary intensity-modulated signals by a delay interferometer (DI). Two schemes, one using the constructive port of the DI and the other using the destructive port, are demonstrated through experiment.