The invention relates to a dispersion-shifted optical fiber comprising a core and cladding, with an index profile of shape consisting of a rectangular central portion surrounded by an annular portion of index lower than the index of the cladding, and then by the cladding, with a zero chromatic dispersion at a wavelength value .lambda..sub.0 lying in the range 1380 nm to 1450 nm, and with chromatic dispersion at 1550 nm lying in the range 8 ps/nm.multidot.km to 12 ps/nm.multidot.km. The invention also relates to the use of such an optical fiber in a wavelength division multiplexed system.