Alcatel

Draka Comteq B.v.

Ludovic Fleury

Pierre Sillard

Louis-Anne De Montmorillon

Pascale Nouchi

Florent Beaumont

Maxime Gorlier

Denis Molin

Lionel Expert

Jean-Florent Campion

Lionel Provost

Max Matau

Alain Bertaina

Bruno Dany

Maxine Gorlier

Christine Labatut

The invention relates to methods of producing and improving an optical transmission line comprising the combination of a line optical fiber and an original or modified module for compensating the chromatic dispersion of said line optical fiber. The modified compensation module is a module for compensating chromatic dispersion of a line optical fiber () in a plurality of contiguous and non-overlapping spectral bands each covering at least 30 nanometers, the module including a structure () carrying a plurality of submodules () at least one of which is separable from the structure (), which are disposed in series, which are interconnected by one or more connections () identifiable to the naked eye without optical measurement and accessible from the exterior without damaging the module, and each of which includes a support to which is fixed at least one optical fiber () for compensating chromatic dispersion, at least one optical fiber () of said plurality of compensation optical fibers () having a compensation ratio from 0.9 to 1.1 for the center wavelength of one of said spectral bands, and at least two submodules () having compensation optical fibers () of different kinds.

Method of producing and improving an optical transmission line, and associated compensation modules

The invention relates to the field of optical fibers for wavelength division multiplex transmission networks. It provides an optical fiber with chromatic dispersion compensation in the S band from 1 460 nm to 1 530 nm having a negative chromatic dispersion at the wavelength of 1 495 nm and at least three core slices, preferably at least four core slices. The single core slice or the first core slice is very deeply buried and preferably has as at the wavelength of 1 495 nm a chromatic dispersion to dispersion slope ratio whose absolute value is from 68 nm to 158 nm.

Optical fiber with chromatic dispersion compensation in the S band

The invention relates to a multiband chromatic dispersion compensation optical fiber comprising successively, from the center toward the periphery, a central slice whose maximum index is higher than the index of the cladding, a buried slice whose minimum index is lower than the index of the cladding, and an annular slice whose maximum index is higher than the index of the cladding and lower than the maximum index of the central slice, a cladding of constant index, and having, on the one hand, at the wavelength of 1550 nm, firstly a chromatic dispersion of less than &#x2212;8 ps/nm.km, secondly a chromatic dispersion to dispersion slope ratio whose absolute value is greater than 750 nm, and thirdly a mode diameter greater than 5 &#x3bc;m, and on the other hand, at the wavelength of 1625 nm, bending losses for a radius of 10 mm that are less than 400 dB/m.

Chromatic dispersion compensation optical fiber

The invention proposes an optical fiber presenting a reference index profile having more than six steps. At a wavelength of 1550 nm it presents chromatic dispersion that is positive, and a ratio of the square of effective area over chromatic dispersion slope that is greater than 100,000 &#x3bc;m.nm.km/ps. The invention makes it possible to improve the propagation characteristics of prior art fibers by optimizing index profile. It can be implemented using conventional techniques for building up preforms by VAD or by MCVD.

Optical fiber of complex index profile

The dispersion managed optical fiber () far use in wavelength division multiplex transmission networks includes longitudinally alternating positive and negative chromatic dispersion optical fiber portions and includes a core having a varying index profile and a cladding having a constant index. Each optical fiber portion (T+, T&#x2212;) has at a wavelength of 1550 nm a chromatic dispersion whose absolute value is from 1 ps/nm.km to 10 ps/nm.km, a chromatic dispersion slope whose absolute value is less than 0.015 ps/nm.km, and an effective area greater than 35 &#x3bc;m. The relative effective area difference at a wavelength of 1550 nm between the positive and negative chromatic dispersion optical fiber portions is less than 7%, and each optical fiber portion (T+, T&#x2212;) has bending losses at a wavelength of 1625 nm less than 0.1 dB for 100 turns with a diameter of 60 mm.

Dispersion managed optical fiber

The invention relates to a method of fabricating an optical fiber with improved control of transmission characteristics. It proposes determining variations in the characteristics of the preform departing from the design characteristics and modifying the diameter of the fiber during drawing as a function of the measured variations. By varying the diameter of the fiber, variations in the preform departing from its design values can be compensated, in other words irregularities of the preform can be smoothed out. This variation limits the effect of preform variations on the propagation characteristics of the fiber.

Method of fabricating an optical fiber with controlled transmission characteristics

The invention provides a step index optical fiber which presents cladding having an index lower than the index of silica and a core with an index higher than the index of silica. The fiber is obtained by drawing a preform made by chemical vapor deposition using a deposition tube of index lower than the index of silica. Inner cladding of index substantially equal to the index of the deposition tube, and then a core of index higher than the index of the inner cladding are deposited in succession therein. The invention makes it possible to obtain a fiber having a large effective area, reduced attenuation, and suitable for being fabricated at low cost by chemical vapor deposition.

Step index optical fiber with doped cladding and core, a preform, and a method of fabricating such a fiber

An optical fiber has three or four core slices including one or more buried slices and a raised central slice. The buried slice or each of the buried slices is very deeply buried. The fiber has a zero dispersion wavelength of less than 1 460 nm. It has a chromatic dispersion in the vicinity of 5 ps/nm.km and a dispersion slope in the vicinity of 0.03 ps/nm.km at a wavelength of 1 550 nm.

Optical fiber for wavelength division multiplex transmission networks

The fiber is adapted to compensate chromatic dispersion and chromatic dispersion slope of a positive chromatic dispersion optical fiber in the U band from 1625 nm to 1675 nm. In that band it has negative chromatic dispersion, negative chromatic dispersion slope, and a chromatic dispersion over chromatic dispersion slope ratio from 100 nm to 600 nm. At a wavelength of 1650 nm it has bending losses less than 100 dB/m with the fiber wound around a 10 mm radius former and bending losses less than 5&#xd7;10dB with 100 turns of the fiber wound around a 30 mm radius former. The dispersion compensating fiber can be used to produce broadband transmission systems for signals with wavelengths up to 1675 nm.

Chromatic dispersion compensating fiber for use in U band optical fiber transmission systems

An optical fiber in which propagation is monomode propagation when incorporated into a cable has, at a wavelength of 1 550 nm, a chromatic dispersion from 3 ps/(nm.km) to 14 ps/(nm.km) and an absolute value of chromatic dispersion slope less than 0.014 ps/(nm .km), and, at a wavelength of 1 625 nm, bending losses measured for a 10 mm radius less than 400 dB/m. The proposed criteria allow use of the fiber over a wide band of wavelengths in a wavelength division multiplex transmission system. The low chromatic dispersion slope simplifies the management of chromatic dispersion in the transmission system.

Optical fiber for a wavelength division multiplex transmission system

The invention provides a fiber with continuously changing chromatic dispersion; it limits the quantity of dispersion-compensating fiber needed in a transmission system to compensate the cumulative chromatic dispersion in the line fiber. The fiber has a higher chromatic dispersion at a first end than at the other end, referred to as the second end. The chromatic dispersion varies along the fiber, decreasing over at least a portion of the fiber. At the first end the chromatic dispersion can be of the order of the dispersion of a conventional line fiber, i.e. close to 8 ps/(nm.km). At the second end the chromatic dispersion can have a value of the order of 4 ps/(nm.km). The fiber is used as the line fiber in a transmission system at the beginning of a section between two repeaters. The chromatic dispersion in the vicinity of the first end limits non-linear effects at the beginning of the section; the decrease of the chromatic dispersion in the fiber ensures that at its second end the fiber can be connected to a fiber having lower chromatic dispersion. The fiber can be produced with an index profile in the shape of a rectangle and a ring by varying only the indices, and not the radii.

Fiber with continuously changing chromatic dispersion

At a wavelength of 1 550 nm an optical fiber has a chromatic dispersion from &minus;12 to &minus;4 ps/(nm.km) and a ratio of chromatic dispersion to chromatic dispersion slope from 250 to 370 nm. Its index profile comprises a rectangle or trapezium with a buried trench and a ring. An optical fiber transmission system uses this kind of fiber to compensate cumulative chromatic dispersion in a line fiber that has at a wavelength of around 1 550 nm a chromatic dispersion from 5 to 11 ps/(nm.km) and a ratio of chromatic dispersion to chromatic dispersion slope from 250 to 370 nm.

Optical fiber for in-line compensation of chromatic dispersion in an optical fiber with positive chromatic dispersion

A chromatic dispersion-compensating fiber adapted to compensate the chromatic dispersion of an SMF or an NZ-DSF having positive chromatic dispersion presents chromatic dispersion which is negative and greater than or equal to &minus;150 ps/(nm.km) at a wavelength of 1550 nm, and a theoretical cutoff wavelength longer than 1800 nm. At 1550 nm, the fiber presents a ratio of chromatic dispersion over chromatic dispersion slope lying in the range 30 nm to 500 nm. The fiber can present a rectangle or a trapezium profile together with a buried trench and a ring. It can be used in a line or in a module to compensate the chromatic dispersion and the chromatic dispersion slope in transmission systems in which the line fiber is an SMF or an NZ-DSF having positive chromatic dispersion.

Fiber for compensating the chromatic dispersion of an NZ-DSF having positive chromatic dispersion

An optical fiber is disclosed for compensating the chromatic dispersion of on optical fiber with positive chromatic dispersion advantageously has, at a wavelength of 1 550 nm, a chromatic dispersion less than &minus;40 ps/(nm.km), or even less than &minus;50 ps/(nm.km), a ratio between the chromatic dispersion and the chromatic dispersion slope from 50 nm to 230 nm, an effective surfaced area greater than 12 &mgr;m and curvature losses less than or equal to 0.05 dB. It is used for in-line compensation of cumulative chromatic dispersion in a line fiber with positive chromatic dispersion. Also disclosed is a fiber optic transmission system using a fiber of the above kind to compensate cumulative chromatic dispersion in the line fiber.

Growing community of inventors

Bois d'Arcy, France

Ludovic Fleury