Properties of the pulse train generated by an actively mode-locked Er-doped fiber laser in the rational-harmonic repetition-rate-doubling regime

We demonstrate for the first time that pulse-to-pulse amplitude fluctuations occurring in the rational-harmonic repetition-rate-doubling regime of actively mode-locked fiber laser are eliminated when modulation frequency is properly tuned. Irregularity of the pulse position in the train is found to be the only drawback of this technique. The irregularity can be reduced to value acceptable for applications by a proper laser design.