HIGH-REPETITION-RATE MODE-LOCKED ER-DOPED FIBER LASERS BY HARMONIC INJECTION LOCKING

We present a novel method for the generation of synchronized short pulses at high repetition rates from Er-doped silica fiber lasers. The method employs coupling of an optical pulse train to a passively mode-locked fiber laser. The injected signal repetition rate is slightly detuned from the modal spacing of the fiber laser, such that a subset of the latter modes is injection locked, yielding a high-repetition-rate pulse train. By injecting a 2-GHz train of relatively broad optical pulses at an average power of 100 mu W, we achieved a train of 6-ps pulses at rates of 40 GHz from the harmonically locked fiber laser. (C) 1995 Optical Society of America