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Tapered fiber phase conjugator for high-power all-solid lasers with high repetition rate

A high power multi-pass diode-pumped solid-state MOPA system with large core diameter tapered quartz fiber as phase conjugator is experimentally investigated. The results of the effects of laser longitudinal mode characteristic, laser pulse width and fiber surface optical quality on SBS reflectivity are presented. Maximum SBS reflectivity of 69.7% is obtained with the repetition rate of 1000 Hz, input pulse energy of 38mJ and pulse width of 24 ns. The phase conjugator is made from a taper shaped quartz fiber with the diameter of 1mm at the input end and 0.4mm at the other end. It has good application prospects in improving the beam quality and compressing the pulse width for high power laser system with high repetition rate.