The aim of our investigation was to develop a technique of producing Bragg’s grating couplers on planar waveguides obtained by means of the sol-gel technique. Introducting a light beam into the waveguide structure is in the case of planar optical systems always an essential technological problem, requiring simple and reproducible solutions without extending the waveguide structure too much. The paper deals with the technology of producing grating couplers by impressing the pattern of the network while forming the planar waveguide structure applying the sol-gel method. The results of investigation on grating couplers obtained in such a way have also been presented. Attention has been drawn to the possibility of using such structures in optoelectronic sensors, particularly gas sensors, including sensors of toxic gases.