Abstract

Direct modulations^1-3 offers an attractive alternative to the more cumbersome mode-locking technique^4,5 in obtaining picosecond pulse trains from laser diodes. A scheme, known as gain switching, consists of pumping a laser diode, which is biased below threshold, with strong sinusoidal or short pulse current. The optical intensity in the laser cavity builds up and decays rapidly, being governed by the stimulated emission and the saturation processes, respectively. The resulting optical pulse width is typically of the order of a few cavity roundtrip time.

© 1981 Optical Society of America