Abstract: The invention relates to a single-mode optical fiber that, for a wavelength of 1550 nm, has an effective area greater than or equal to 60 &mgr;m2, chromatic dispersion lying in the range 3 ps/(nm.km) to 14 ps/(nm.km), a chromatic dispersion gradient in the range 0 ps/(nm2.km) to 0.1 ps/(nm2.km), and a ratio between the effective area and the chromatic dispersion gradient that is greater than or equal to 1000 &mgr;m2.nm2.km/ps, as well as a zero chromatic dispersion wavelength shorter than 1480 nm. The fiber thus has both a large effective area and a shallow chromatic dispersion gradient, and it is thus well suited to wavelength division multiplexed (WDM) transmission. The invention also relates to a WDM optical fiber transmission system that uses such a fiber as the line fiber.

Abstract: A monomode dispersion shifted optical fibre having an effective core area greater than 100 &mgr;m2, characterized in that it has a chromatic dispersion cancellation wavelength &lgr;0 from 1 400 nm to 1 500 nm and low curvature losses.

Abstract: The invention provides a monomode optical fiber having, at a wavelength of 1550 nm: an effective section area greater than or equal to 60 &mgr;m2; chromatic dispersion close to 8 ps/(nm.km); a chromatic dispersion slope of absolute value less than 0.07 ps/(nm2.km). In the range of wavelengths used in a WDM transmission system, typically 1530 nm to 1620 nm, the fiber has chromatic dispersions greater than 7 ps/(nm.km), thereby making it possible to limit non-linear effects. The invention also provides a WDM optical fiber transmission system using such a fiber as a line fiber. The small slope of its chromatic dispersion is an advantage in such a system.

Abstract: A stepped index optical fiber is disclosed having a chromatic dispersion cancellation wavelength less than 1 280 nm or even 1 250 nm. The fiber can be used for wavelength-division multiplex transmission not only in the window around 1 550 nm but also in the window around 1 300 nm. The chromatic dispersion in the second window enables transmission without excessively penalizing non-linear effects. A fiberoptic transmission system which uses the above fiber as line fiber is also disclosed.

Abstract: In a method of shrinking a tubular optical fiber preform with a doped silica core the preform is placed on a glassmaking lathe to rotate it about an axis, a torch is moved parallel to the axis in front of the preform to shrink it and collapse it in a number of passes, and during an etching pass a mixture of oxygen and a fluorine precursor gas is injected through one end of the incompletely collapsed preform to eliminate a certain layer from the core. During the etching pass, a certain value of the pressure of the gaseous mixture at the end of the preform is determined and the speed of the torch is slaved to this pressure value. Controlling the speed of the torch stabilizes the pressure of the gaseous mixture inside the preform, which longitudinally homogenizes the diameter of the core and the refractive index difference relative to an optical cladding around the core.