The paper deals with the basic set-up of single-frequency microchip laser - so called Lyot filter configuration. Description of its operation and practical realization is given. Some results obtained for Nd:YAG/KTP microchip laser are presented. The evidences of single-frequency operation and its limits are emphasized. Described construction constitutes the base for building the frequency stabilization of green 532 nm microchip laser.

In this paper our results of investigation on a pump power combiner in a configuration of 7×1 are presented. The performed combiner, with pump power of 80–85% transmission level, was successfully applied in a thulium doped fibre laser. The performed all-fibre laser setup reached a total CW output power of 6.42 W, achieving the efficiency on a 32.1% level