Abstract

A new modification of a passive Q-switching technique in a laser with an isotopic saturable absorber is suggested and implemented in a multi- segmented injection laser. The idea is to transport the most part of the excited absorber population to the amplifier. The carrier transport time must be shorter than the spontaneous recombination time in the absorber. The three-section AIGaAs/GaAs DH laser has been fabricated with two 200-µm long amplifier segments and a 40-µm long absorption section placed between them. To pump the laser, current pulses 2-100 ns long with an amplitude of 0.3–2 A were applied. The reverse dc bias on the saturable absorber was changed within the range of 10–20 V. There is a strong electric field of 10³–10⁴V/cm in the drift gaps between the amplifiers and the absorber. The carrier transport in the electric field from the absorber results in its ultrafast time recovery. Moreover, the transported excited particles can take part in the stimulated emission and increase the laser’s effectiveness and output pulse power.

© 1988 Optical Society of America