Abstract

The maximum span length of high-speed optical transmission systems operating in the 1.5-μm window can be severely limited by dispersion effects if existing fiber routes of 1.3-μm optimized conventional single-mode fibers (SMFs) are used. The new method of dispersion-supported transmission (DST) permits optical transmission beyond the conventional dispersion limit.¹ A directly modulated laser diode can be used to generate an optical frequency-shift-keyed (FSK.) signal. Because of the fiber dispersion, this optical frequency modulation is converted to an amplitude modulation. After direct detection, the original data signal can be recovered by electrical low-pass filtering. This principle of operation is illustrated in Fig. 1, where residual amplitude modulation of the transmitter is also taken into account.

© 1994 Optical Society of America