Research On Q-switched All-fiber Er³⁺/Yb³⁺ Co-doped Double Cladding Fiber Lasers

Q-switched fiber lasers have great application potential in free space optical communication, remote sensing, medical applications and other fields with Er³⁺/Yb³⁺ co-doped double cladding fiber as gain medium. These lasers are characterized by high peak power, Compact structure, free of maintenance and a series of advantages. The dissertation is focused on Q-switched all-fiber Er³⁺/Yb³⁺ co-doped double cladding fiber laser in experiment. The main research contents include the following:1?All-fiber self Q-switched laser was designed with gain fiber itself as absorber. self Q-switched pulse can be obtained by the laser with pulse width from 5?s to 40?s and repetition rate from 5.8k Hz to 110 k Hz in pump power range from 87 m W to 176 m W. A reasonable explanation for the pulse is given for the pulse.2?Acousto-optic all-fiber Er³⁺/Yb³⁺ co-doping fiber laser has been presented, whose repetition rate range is given under different pump power. The change of pulse, power and the causes of them are analyzed when modulation rate is out of the repetition rate range. The output of the laser is analyzed versus pump power, modulation rate and transmittance. The minimum width and average power are 1.5us and 180 m W. When the pump power is 0.9W and modulation frequency is 3k Hz, the pulse is obtained with the peak power of 5 W, single pulse energy of 50?J. The laser center wavelength is 1550.3 nm and the line-width is 0.07 nm.3?Q-switched Er³⁺/Yb³⁺ fiber laser in MOPA configurations has been designed taking advantage of the acousto-optic Q-switched pulses as seed source,Whose average power more than 1.16 W. The peak power increase from 5W to 42 W when the seed source with the pump power of 0.9W and modulation rate of 3k Hz was injected into the amplifier with the pump power is 5.7W. Its magnification is more than 8 times. The seed source amplification of power, changes in time domain and frequency domain features were obtained by experiment.