METHOD FOR POINT-BY-POINT INSCRIPTION OF FIBRE BRAGG GRATINGS BY FEMTOSECOND LASER RADIATION Russian patent published in 2022 - IPC G02B6/28 

FIELD: instrument manufacture.

SUBSTANCE: invention relates to optical instrument manufacture, to fibre optics. Method for inscribing fibre Bragg gratings (FBR) includes moving the fibre with a set velocity profile and subjecting the fibre core point-by-point to pulses of focused femtosecond laser (FSL) radiation in order to modulate the refractive index in the area of formation of the FBR structure. The point-to-point exposure to FSL radiation pulses with the repetition frequency of 10 kHz or lower is implemented through multiple passes, in N cycles, over the area of formation of the FBR from the initial point to the end point, storing the coordinates of both points. The initial track is formed first; then, in the subsequent passes, the exposure to FSL radiation pulses is implemented with account fir the stored coordinates of the points of said initial track; wherein the fibre in the area of formation of the FBR structure is returned to the initial position or to a position shifted relative to the initial position by a set amount after each pass, and the moment of emission of the first pulse of FSL radiation is aligned in time, with an accuracy of 10 ms or more, with the moment of arrival of the initial point of the FBR to the inscription area.

EFFECT: increase in the reproducibility and controllability of changing the parameters of the FBR in the process of inscribing.

7 cl, 5 dwg