RELAXATION OSCILLATIONS IN FIBER-GRATING-TUNED ERBIUM-DOPED FIBER LASERS

Relaxation oscillations were studied experimentally and theoretically in a fiber-grating-tuned erbium-doped fiber laser with a doped fiber l ength of 7 to 9 m. Two regions of amplitudes in the relaxation oscilla tions were observed. For small-amplitude oscillations, the measured re laxation oscillation frequency agreed with that given by an approximat e equation. For large-amplitude oscillations, chirping in the relaxati on oscillation frequency was observed. A numerical analysis based on r ate and propagation equations was performed to analyze this chirping. The results qualitatively agreed with those of the experiment. Wavelen gth tuning was also performed using a Peltier device. The tuning range was 2.1 nm for a grating in the 1.53-1.5 mu m region.