Ultrafast optical pulses and solitons for advanced communications

We describe mode-locked fiber lasers in the GHz region and their applications to high-speed optical communication such as soliton and tera bit/s OTDM transmission. As for the soliton communication, such a pulse train was very advantageous since the fiber laser could directly generate a transform-limited sech pulse using a soliton effect in the fiber cavity. It is also useful as an input pulse for an optical pulse compressor using the adiabatic soliton compression effect. These compressed pulses were used for a tera bit/s OTDM transmission experiment, realizing for the first time a 1.28 Tbit/s OTDM transmission over 70 km. Since the mode-locked fiber lasers can easily generate a clean transform-limited short pulse train, they are applicable to a variety of advanced optical communication technologies.