SINGLE-MODE FIBRE WITH SHALLOW GROOVE, INSENSITIVE TO BENDING LOSSES, AND CORRESPONDING OPTICAL SYSTEM Russian patent published in 2021 - IPC G02B6/28 G02B6/36 

FIELD: fibres.

SUBSTANCE: single-mode optical fibre, insensitive to bending losses, has a mode field diameter greater than or equal to 9.0 mcm at a wavelength of 1,310 nm, the refractive index profile of the core has a trapezoidal shape. The central part of the core has a radius r₀ and a refractive index n₀, and the transition section of the trapezoidal refractive index profile of the core is in the range from the radius r₀ to the radius r₁>r₀ at a trapezoidal ratio r₀/r₁ of the radius r₀ of the central part of the core to the radius r₁ of the transition section from 0.1 up to 0.6. The shell is comprised of at least one groove with a low refractive index in the range from a radius r₂≥r₁ to a radius r₃>r₂ and with a refractive index n_t, and the outer shell is located in the range from the radius r₃ to the end of the glass part of the single-mode fibre and has a refractive index n₄, the difference Δn_t=n_t-n₄ of the refractive indices of the groove and the outer shell is from -2×10^-3 to -0.9×10^-3.

EFFECT: provided are single-mode fibre with an improved refractive index profile, easily spliceable with a standard single-mode fibre without a groove.

14 cl, 17 dwg, 13 tbl