Abstract
Mode-locking and gain-switching of semiconductor lasers have been reviewed from a view point of an optical short pulse generator for soliton transmission. A new approach from an external modulation using an electroabsorption modulator to generation of transform- limited optical short pulses is demon-strated. Transform-limited optical pulses up to 20 GHz repetition rates were generated just using a sinusoidal modulation of an InGaAsP electroabsorption modulator without any optical resonators and optical filters. The shape of the modulator-generated pulse is very closed to sech2 shape, and both the pulse width and the repetition rate can be easily varied by electrical signals. The promising future of the simple and stable optical pulse generation using the electroabsorption modulator was confirmed by 2.5 Gb/s-6400 km soliton data transmission using circulating loop experiments.
