DEVICE FOR CREATION OF PERIODIC STRUCTURES OF REFRACTION INDEX INSIDE TRANSPARENT MATERIALS Russian patent published in 2019 - IPC G02B6/00 

FIELD: instrument engineering.

SUBSTANCE: invention relates to the field of optical instrument-making and can be used for fabrication of fiber Bragg gratings, long-period grids of the refraction index. Device consists of optically series-connected source of femtosecond laser radiation, rotary mirror, first converging lens, refractive plane-parallel plate made of optically transparent material and having the shape of rectangular parallelepiped, a second converging lens, a microlens and a transparent ferrule with a polished side face for accommodating a fiber-optic guide. Plate is placed with offset from beam-neck between first and second converging lenses and is installed with possibility of rotation about axis perpendicular to optical axis, optical circuit for controlling lateral displacement of laser radiation beam in focal plane of microlens defined by formula , where θ is the angle of rotation of the refractive plate, d is the thickness of the refractive plate along the optical axis at θ=0 rad, n is refractive index of refractive plate, ƒ₁ – focal length of microlens, ƒ₂ is focal distance of second lens. Distance between first and second converging lenses L₁=ƒ₃+ƒ₂+(n-1)d/n, where ƒ₃ is focal distance of first convergent lens, and distance L₂ from the second lens to the input aperture of the microlens is equal to the focal length of the second converging lens. A ferrule with a fiber-optic guide placed in it is located so that the core of the fiber-optic guide lies in the focus of the microlens.

EFFECT: high reflection coefficient of fiber Bragg gratings and speed of their manufacturing, as well as expansion of types of recorded structures.

1 cl, 7 dwg