Optimized diode-pumped passive Q-switched ytterbium–erbium glass laser

A model taking into account the up-conversion processes involving the upper laser level and the presence of the unpumped regions within the active element along with the lasing transitions has been developed for the passive Q-switched ytterbium–erbium glass laser which was transversally pumped by the laser diode arrays. The results of the simulation allow determining the working point providing the stable and long-term operation of the laser. The correctness of the proposed optimized model was experimentally proved by means of a comparative investigation of the utmost permissible output lasing characteristics. The maximum output lasing pulse energy up to 16.5 mJ with the pulse duration of 11.5–16.0 ns at the wavelength of 1.535 μm has been achieved with the rectangular active element for the length of 32 mm.