Analysis of the effect of hydrogenation of photosensitive fibres on the parameters of the periodic structures produced

An inscription of a Bragg grating on a typical telecommunications fibre is difficult to obtain. In inscribing a structure, special fibres with an increased germanium content or classic fibres subjected to the hydrogenation process are used. The following article analyses the dependence of the hydrogen pressure on the parameters of the structures produced, such as grating reflectivity, Bragg wavelength or full width at half maximum (FWHM). The article also verifies how the pressure in the hydrogenation process affects the time of inscribing structures. Two types of fibre were subjected to photosensitisation: the classic one and one with a higher content of germanium. The hydrogenation process was performed at three pressures of 50 bar, 100 bar and 190 bar. Hydrogenation took place under the ambient temperature conditions of the room in which the chamber was located.