Abstract

All-optical active mode locking is currently of great interest for the generation of high-repetition rate pulse trains^[1] and in all-optical clock-recovery circuits^[2], which are some of the key components of ultra-high bit rate communication systems^[3]. Though active mode locking has been known for some 30 years^[4], only recently has the advent of high-quality single-mode rare-earth-doped fibers^[5] enabled the replacement of the electronic modulator with its all-optical equivalent. In this technique an optical control pulse is used to periodically perturb the phase of the fiber (or waveguide) laser via cross-phase modulation. By the generation of side-bands the laser modes of the signal may then be locked to produce an all-optical equivalent of FM mode locking.

© 1993 Optical Society of America