OPTICAL FIBER WITH SLIGHT SLOPE OF DISPERSION CHARACTERISTIC IN REGION OF FREQUENCIES OF ERBIUM AMPLIFIER Russian patent published in 1999 - IPC

FIELD: optical systems with spectral frequency division multiplex of channels operating with erbium-doped fiber amplifier. SUBSTANCE: proposed optical fiber has chromatic dispersion which absolute value in the range of wave lengths from 1530 to 1565 nm exceeds 0.5 пс/(нм.км) and slope of dispersion characteristic is less than 0.05 пс/(нм².км). Optical fiber has losses not exceeding 0.20 dB/km and is comparatively low-sensitive to bending. Effective area of its cross-section exceeds 50 μm². Optical fiber includes central conductor made of transparent material with maximum refractive index n₁ and layer of material having refractive index n₂ deposited on it on outside and forming sheath. Central conductor has ring of transparent material with minimum refractive index n₃ that is less than n_e. Refractive indices should meet following conditions: 0.50 << (n₁-n₂)/n₂ <0.70 and -0.30 <(n₃-n₂)/n₂ <-0.05. Description includes examples of usage of fibers with slight slope of dispersion characteristic both for positive and negative dispersion. EFFECT: low optical losses. 10 cl, 9 dwg