METHOD OF FORMING ARRAY OF BRAGG FIBER GRATINGS WITH DIFFERENT REFLECTION WAVELENGTHS Russian patent published in 2019 - IPC G02B5/18 G02B6/34 G02F1/125 

FIELD: optics.

SUBSTANCE: invention relates to fibre-optic technologies, in particular to optical fibres, which have in the core quasi-distributed structures of fibre Bragg gratings (FIR) differing by periods on a single segment of optical fibre. Method of forming array of VBR with different wavelengths of reflection using a Talbot interferometer consists in irradiation of single-mode optical fibre with chemical composition of core of 3.5 % GeO₂, 96.5 % SiO₂, preliminary subjected to low-temperature hydrogen treatment, KrF pulses of excimer laser system installed in magnetic holders with tension of not more than 0.02 N, for recording each separate array of VBR array, calculating the period of the interference pattern for the angle of rotation of the interferometer mirrors in accordance with the experimentally determined effective refraction index. Said radiation is preceded by calibration of VBR with one pulse with low reflection coefficient, having previously determined the reflection wavelength of said recording calibration grid, for this purpose, first recording test gratings, recording the initial and final reflection wavelength and calculating the difference between said values, determining the Bragg resonance FRG shift value during its recording time to a predetermined reflection coefficient, and calibration grid is recorded with wavelength smaller by a value equal to Bragg resonance VBR shift value. Wavelength of the recorded calibration grid is recorded, and if its wavelength does not correspond to the specified value, the period of the interference pattern is recalculated in accordance with the Bragg condition for turning the mirrors of the interferometer to the required correcting angle.

EFFECT: technical result is providing control of diffraction efficiency of each array and formation of VBR arrays in a wide spectral range and high accuracy of reflection wavelengths in the array.

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