Dispersion slope compensating optical fiber

Abstract

The invention relates to a dispersion slope compensating optical fiber which compensates the chromatic dispersion and dispersion slope of a positive dispersion slope optical fiber such as TRUE WAVE and increases reliability of wavelength division multiplex transmission in a wavelength from 1530 nm to 1610 nm. The center core (3) is covered by a side core layer (4), and the outside thereof is covered by a cladding layer (5), wherein the relationship between the relative refractive index differences .DELTA.1, .DELTA.2, .DELTA.3 of the center core (3), side core layer (4) and cladding layer (5) and pure SiO.sub.2 glass is established to be .DELTA.1) .DELTA.3) .DELTA.2, .DELTA.2/.DELTA.1=Rd.ltoreq.-0.45, and .DELTA.1.gtoreq.1.2%. The average dispersion slope in a wavelength from 1530 nm to 1610 nm is established to be -0.6 ps/nm.sup.2 /km or less, and the value obtained by dividing the dispersion value in the same wavelength by a dispersion slope is made 160 or less, wherein by connecting the dispersion shifted optical fiber to TRUE WAVE, whose average dispersion slope in said wavelength is approximately 0.07 to 0.1 ps/nm.sup.2 /km and whose dispersion value is greater by approximately 15 to 60 times than the dispersion slope, with a length which is shorter by approximately one-ninth than the length of TRUE WAVE, the dispersion in the said wavelength band can be drawn to nearly zero dispersion.