| Singles-frequency fiber laser in pulsed mode could provide sufficient peak power and excellent laser beam quality.More importantly,the diversity of time-domain characteristics in pulsed SFFL cover a wide range of pulse duration,which meets the requirement of various application,such as laser ranging,Lidar,high-speed photograth.However,researches on short-linear-cavity single-frequency Q-switched fiber laser and frequency-modulated Q-switched fiber laser have not been developed as a hotpot,which limits its applications in space communication system and airborne Lidar system.Therefore,it is neccessary to develop the research of short-linear-cavity single-frequency Q-switched fiber laser and frequency-modulated Q-switched fiber laser to enhance its application value and promote its application range.In this thesis,our experiments are based on single-frequency pulsed fiber laser,and the research contents and the main results are as follows.(1)The Q-switching and frequency excursion were realized by a tensile-induced period modulation utilizing a piezo electrical transducer.A external modulated signal is implemented on the piezo electrical transducer to periodly adjust the quality factor of cavity.Over 375 MHz frequency-tuning range is achieved with the highest peak power reaching 6.93 W.(2)Based on the injection of a frequency-modulated single-frequency laser and the modulation of a fiber coupled acoustic-optics modulator,Over 1.05-GHz maximum frequency excursion were obtained.Besides,no instability was observed in the output pulse of the ring cavity while the frequency-modulating signal was implemented.(3)By employing a semiconductor saturable absorber mirror(SESAM)as the Q-switching,a single-frequency pulse fiber laser is realized in the ultra-compact cavity with efficient length of 20 mm.Further,we used polarization-maintaining fiber Bragg grating to ensure stably dual-wavelength lasing,and the Q-switched pulses at two wavelengths can be temporally synchronized in the experiment. |
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