Abstract: The invention relates to a device for locking a nut (13) in a tightened position on a rotary shaft (12), said rotary shaft (12) being hollow at least at one end (14). The locking device comprises a plurality of outer notches (16) formed in a face of the nut (13), said outer notches (16) extending parallel to a longitudinal axis (X) of the nut (13), a plurality of inner notches (15) formed in the end (14) of the rotary shaft (12), said inner notches (15) extending parallel to a longitudinal axis (X) of the rotary shaft (12), and a ring (18) suitable for being installed inside said end (14) of the rotary shaft (12) and presenting at least one first radial finger (19) for being received both in one of the inner notches (15) and in one of the outer notches (16) with the nut (13) being in a tightened position and the two notches (15, 16) housing said first radial finger (19) being at least partially in alignment in a radial direction.

Abstract: The invention relates to a device for locking a nut (13) in a tightened position on a rotary shaft (12), said rotary shaft (12) being hollow at least at one end (14). The locking device comprises a plurality of outer notches (16) formed in a face of the nut (13), said outer notches (16) extending parallel to a longitudinal axis (X) of the nut (13), a plurality of inner notches (15) formed in the end (14) of the rotary shaft (12), said inner notches (15) extending parallel to a longitudinal axis (X) of the rotary shaft (12), and a ring (18) suitable for being installed inside said end (14) of the rotary shaft (12) and presenting at least one first radial finger (19) for being received both in one of the inner notches (15) and in one of the outer notches (16) with the nut (13) being in a tightened position and the two notches (15, 16) housing said first radial finger (19) being at least partially in alignment in a radial direction.

Abstract: A luminous turning button for an electric circuit, including a handle mounted to pivot about an axis to actuate at least one electric switch unit and that is illuminated by a light source substantially disposed along the axis. The handle includes a cap forming a disk and a gripping tab that protrudes in a diametral plane. The cap is made of translucent or transparent material capable of allowing the light to travel to the outside, the gripping tab being hollow and covering an integrated mechanical base made of opaque material.

Abstract: A luminous turning button for an electric circuit, comprising a handle (20) that is mounted so as to pivot about an axis (X) to actuate at least one electric switch unit (12) and is illuminated by a light source (S) substantially disposed along the axis (X), the handle (20) comprising a cap (22) forming a disk (22B) and a gripping tab (22A) that protrudes in a diametral plane, characterized in that the cap (21) is made of translucent or transparent. material capable of allowing the light to travel to the outside, the gripping tab (22A) being hollow and that it covers an integrated mechanical base (21) made of opaque and mechanically strong material.

Abstract: A gas pumping system of the invention enables gas to be pumped from a process chamber (1) in order to regulate its pressure as a function of process steps. The system comprises a primary pump (2), a secondary pump (8), an inert gas injection device (6), and a regulator valve (4). The primary and/or secondary pump (2 and/or 8) is controlled in speed in order to regulate variations of greater amplitude. The regulator valve (4) is controlled in opening in order to regulate variations that are small amplitude and fast. The inert gas injection (6) is controlled in flow rate in order to regulate medium amplitude variations. This provides great reaction stability and a wide range of possible variation for the conditions in the process chamber (1).

Abstract: The invention relates to a dispersion-shifted single-mode optical fiber having an effective area greater than or equal to 60 &mgr;m2. This fiber is characterized by the fact that it has a zero chromatic dispersion wavelength &lgr;0 that is greater than 1585 nm and chromatic dispersion at 1550 nm that is greater in absolute terms than 3 ps/nm.km. The invention is applicable to wavelength division multiplexed transmission systems, and makes it possible to limit non-linear effects, such as four-wave mixing, and to limit the use of dispersion-compensating fiber.

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: The invention relates to a dispersion shifted monomode optical fiber which, in the wavelength range 1400 nm to 1650 nm, presents both a chromatic dispersion maximum and a chromatic dispersion slope of absolute value less than 0.05 ps/nm2·km. Advantageously, the maximum in the wavelength wave 1400 nm to 1650 nm is a single maximum. The fiber also presents dispersion having a slope of absolute value less than 0.03 ps/nm2·km in the wavelength range 1530 nm to 1580 nm. The fiber of the invention is particularly suitable for wavelength division multiplexed transmission systems.

Abstract: The invention concerns a monomode optical fiber having at a wavelength of 1550 nm a dispersion slope from −0.8 ps/nm2.km to −0.5 ps/nm2.km and a chromatic dispersion from −130 ps/nm.km to −90 ps/nm.km, the fiber having a cladding and a core whose index profile features a central part having an index higher than that of the cladding, a ring having an index higher than that of the cladding and lower than that of the central part, and a trench between the central part and the ring having an index lower than that of the cladding, and the use of a fiber of this kind to compensate dispersion. The fiber of the invention finds applications in high bit rate transmission systems in particular. The invention also concerns a wavelength division multiplex optical fiber transmission system comprising at least one section of fiber in accordance with the invention.

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 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 &lgr;0 lying in the range 1380 nm to 1450 nm, and with chromatic dispersion at 1550 nm lying in the range 8 ps/nm·km to 12 ps/nm·km. The invention also relates to the use of such an optical fiber in a wavelength division multiplexed system.

Abstract: The invention relates to a dispersion-shifted single-mode optical fiber having: cladding of given refractive index (ns); and a fiber core having an index profile that is Gaussian with a pedestal, i.e. a “dual shape core” index profile; said fiber being characterized in that the index profile of the fiber core has an outer ring of index (n3) greater than the index (ns) of the cladding. The invention provides better control over the wavelength at which chromatic dispersion is zero, while conserving the other transmission characteristics of known fibers, such as mode diameter and attenuation.

Abstract: The invention relates to a dispersion-shifted single-mode optical fiber having an effective area greater than or equal to 60 &mgr;m2. This fiber is characterized by the fact that it has a zero chromatic dispersion wavelength &lgr;0 lying in the range 1400 nm to 1480 nm, and bending losses of less than 0.05 dB at 1550 nm for a winding of 100 turns of the fiber around a radius of 30 mm. The invention is applicable to wavelength division multiplexed transmission systems, and makes it possible to limit non-linear effects, such as four-wave mixing, and to limit the use of dispersion-compensating fiber.

Abstract: The invention relates to a system for regulating the pressure in an enclosure (1) that is to contain processed gas for manufacturing semiconductor components or micro- or nano-technology devices, the enclosure being connected by pipework (2) to a pump unit (3) comprising a dry mechanical primary pump (4) and at least one secondary pump (5). According to the invention, the system further comprises a speed controller (6) controlling simultaneously the speeds of rotation of the dry mechanical primary pump (4) and of said at least one secondary pump (5).

Abstract: The invention relates to an optical fiber amplifier (OFA) having a controllable heating system for adjusting and stabilizing the temperature of a fiber, wherein the heating system comprises a heat-generating fiber coating (TC) that has an electrical connection for applying a heating voltage or injecting a heating current (I1, I2) for the purpose of heat generation, wherein the heat-generating fiber coating (TC) surrounds at least a part of the fiber (OF), and also a method therefor.

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: The invention relates to a dispersion-shifted single-mode fiber having cladding of given refractive index (ns) and a fiber core having an index profile that is in the shape of a trapezium, a triangle, or a rectangle, together with a first ring, the index profile of the fiber core having an outer, second ring of index (n3) greater than the index of said cladding (ns), said fiber being characterized in that the index (n3) of said second ring is greater than or equal to the index (n2) of said first ring. The invention provides better control over the wavelength at which chromatic dispersion is zero, while conserving the other transmission characteristics of known fibers, such as mode diameter and attenuation.

Abstract: The invention proposes to fabricate an optical fiber by drawing a preform including several layers, at least one of which has a different viscosity to the other layers at the drawing temperature. The drawing tension is varied during drawing to obtain a fiber having a constant diameter and a varying profile. The chromatic dispersion of the fiber can therefore vary along the fiber. The invention applies to the fabrication of dispersion managed fibers (DMF).

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.