摘要： The erbium-doped active media allow to generate laser radiation in spectral range 2.7-2.94 μm if the laser transition 4I11/2→4I13/2 is used. Since the laser radiation in this spectral range is strongly absorbed in the water these lasers can be used in medicine (surgery, ophthalmology, urology). Nowadays, there are many papers deal with erbium-doped bulk active media operating in free-running or Q-switched regime, nevertheless, the passively mode-locked lasers are mainly built with Er-doped fibres. However, the compact passively mode-locked erbium-doped bulk lasers could offer a higher repetition rate and smaller dimensions. To date, the shortest laser pulses (1.78 ns) generated with erbium bulk laser (Er:CaF2-SrF2) was obtained in Q-switched mode-locked regime. In this paper, the SESAM mode-locked compact Er:YLF laser with the picosecond pulses and GHz repetition rate for the first time, according to the author’s knowledge, is presented.