LOW-LOSS AT BENDS OPTICAL FIBER Russian patent published in 2020 - IPC G02B6/02 G02B6/36 

FIELD: optical fiber engineering.

SUBSTANCE: single-mode optical fiber includes (I) a core containing outer radius r₁, maximum increment Δ_1max of refraction index in percentage and alpha core, α, greater than 5; and (II) a shell surrounding the core. Envelope comprises (i) an inner region of the shell having an outer radius r₂ and an increment Δ₂ refraction indices in percentage, wherein Δ_1max> Δ₂. Shell also comprises (ii) a channel area surrounding the inner region of the shell, wherein the channel area has an outer radius r₃, wherein r₃>10 mcm, and increment Δ₃ refraction indices in percentage. Besides, the shell contains (iii) external area of the shell, having concentration of chlorine ≥1.2 wt %, surrounding channel area and containing increment Δ₄ refraction indices in percentage; wherein Δ_1max>Δ₄, and Δ₂>Δ₃, and Δ₄>Δ₃ and wherein the difference between Δ₄ and Δ₃≥0.12 %.

EFFECT: technical result consists in enabling reduction of optical losses at fiber bends.

26 cl, 7 dwg, 3 tbl