Dynamic gain induced pulse shortening in Q-switched lasers

Optoelectronics Research Centre, Tampere University of Technology, P.O. Box 692, Tampere 33101, Finland.
Optics Letters (Impact Factor: 3.29). 06/2008; 33(9):1011-3. DOI: 10.1364/OL.33.001011
Source: PubMed


We describe a novel mechanism of pulse shortening in a Q-switched laser induced by the gain compression effect under strong pumping conditions. The pulse shortening requires a large variation of the gain excursion during the saturation process and benefits from the large volume of the gain medium. The effect has been experimentally demonstrated using a passive Q-switched Tm/Ho-doped fiber laser that shows gain-induced pulse compression from 800 ns down to 160 ns when the pump threshold is exceeded by 15 times.

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    • "The pulse repetition rate increased from ß35 to ß60 kHz when the pump power was enlarged, while the output pulse width decreased from ß3.54 to ß1.71 μs. These temporal behaviours that depended on the pump power are a phenomenon typically observed in saturable absorber-based passively Q-switched lasers [41], [45], [54]. Finally, we measured the average output power and its corresponding pulse energy, as shown in Fig. 7. "
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