CLADDING-PUMPED PASSIVE HARMONICALLY MODE-LOCKED FIBER LASER

A passive harmonically mode-locked fiber laser cladding pumped by a br oad-area diode-laser array is described. Harmonic mode locking is obta ined in a frequency range from 33.3 to 128.6 MHz, where the higher fre quency limit is imposed because of insufficient available pump power. The maximum pulse jitter in one cavity round-trip time is between 300 and 50 ps in the whole frequency range, and the sidebands in the frequ ency domain are suppressed by as much as 50 dB. 600-fs bandwidth-limit ed pulses with pulse energies of as much as 20 pJ are obtained, giving rise to an average output power as great as 2.5 mW. (C) 1996 Optical Society of America.