Abstract

In recent years, the semiconductor laser (SL) ability to generate pulse sequences with repetition rate in microwave region has been demonstrated. This ability is based on the fact that even tiny carrier modulation effectively couples the dominant longitudinal mode with a side one provided that the side mode gain deficit is small. For a Fabri-Perot SL, the gain dispersion yields frequency range of the effective mode interactions about 100 GHz.^1,2 In that case, mode locking can be achieved by either current modulation or using saturable absorber.² In principle, this limitation can be even overcome, at least for two interacting modes, by using short compound-cavity (CC) SLs since their frequency-dependent cavity loss enables to control side mode gain deficit by appropriate laser design, and even to tune both mode spacing and mode losses by using phase-adjusting sections.

© 1994 Optical Society of America