OPTICAL FIBER FOR WIDENED SPECTRAL BAND Russian patent published in 2004 - IPC

FIELD: fiber-optical communication lines. SUBSTANCE: invention is intended for fiber-optical communication lines with multiplexing of channels according to wave lengths in widened range of wave lengths between 1530 and 1650 nm. Fiber includes core incorporating internal core with first difference of refractive index, first layer radially enveloping internal core along length of fiber and showing second difference of refractive index under zero, second layer radially enveloping first layer along length of fiber and showing third difference of refractive index, third layer radially enveloping second layer along length of fiber and showing fourth difference of refractive index over zero and glass jacket surrounding glass core and showing difference of refractive index in substance equal to zero. Second layer has width in range from 1 to 5 mcm, third difference of refractive index is less than 40% of mentioned second difference of refractive index in absolute value. EFFECT: diminished optical losses. 24 cl, 14 dwg