A Few Mode Fiber supporting 25 or 30 LP guided modes comprises: A graded index core with a α-profile, a radius R1 (at 0 refractive index difference) between 21.5 and 27μm and a maximum refractive index difference Dn1 between 12.5x10-3 and 20x10-3, and an end of the α-profile at a radius R1b, with index difference Dn1b; A trench surrounding the core with radius R3 between 30 and 42μm and refractive index difference Dn3 between -15.10-3 and -6.10-3, An intermediate depressed trench with a radius R2, with R1b=0.5x10-3, Min(Dn1b, Dn2) < -1.5x10-3, and for I Dn1b-Dn2 | <0.5x10-3, Dn2 is between -5x10-3 and -3.5x10-3.
A Few Mode Fiber supporting 25 or 30 LP guided modes comprises: A graded index core with a α-profile, a radius R1 (at 0 refractive index difference) between 23 and 27μm and a maximum refractive index difference Dn1 between 14.10-3 and 17.10-3, and an end of the α-profile at a radius R1b, with index difference Dn1b; A trench surrounding the core with radius R3 between 30 and 40μm and refractive index difference Dn3 between -15.10-3 and -6.10-3. Such a FMF shows a specific design of the interface between the core and the cladding such that R1b>R1, Dn1b between -10.10-3 and -3.10-3, and Dn1b - Dn3≥ 0.9x10-3.
G02B 6/028 - Fibres optiques avec revêtement le noyau ou le revêtement ayant un indice de réfraction progressif
G02B 6/036 - Fibres optiques avec revêtement le noyau ou le revêtement comprenant des couches multiples
3.
METHOD OF QUALIFYING WIDE-BAND MULTIMODE FIBER FROM SINGLE WAVELENGTH CHARACTERIZATION USING EMB EXTRAPOLATION, CORRESPONDING SYSTEM AND COMPUTER PROGRAM.
The present disclosure concerns a method of qualifying an effective bandwidth of a multimode optical fiber at a first wavelength λ1; using DMD data of the fiber measured a second wavelength λ2. Data representative of a Radial Offset Delay, a Radial Offset Bandwidth and a Relative Radial Coupled Power of the fiber are derived from the DMD data at the second wavelength λ2. A transformation is performed on the ROD data and ROB data at the second wavelength λ2 to obtain corresponding ROD data and ROB data at the first wavelength λχ. An effective bandwidth of the fiber at the second wave- length λ2 is computed using the ROD data and the ROD data at the first wavelength λ1 and the PDMD data at the second wavelength λ2.
The invention relates to a method for selecting wide-band multimode optical fibers from a single wavelength, the method comprising the following steps of, for each multimode optical fiber: obtaining (300) a first DMD plot using a measurement of DMD carried out at a first single wavelength, obtaining (310), from the first DMD plot, a first multimode fiber specification parameter; and for each fiber: obtaining (320), from the first DMD plot, a curve representative of a radial offset delay, called ROD curve, as a function of the radial offset value; applying (330) a linear fit on the ROD curve for at least two radial offset value ranges; obtaining (340) from the linear fit and for each radial offset value range, an average radial offset delay slope, called ROD slope; selecting (350) the multimode optical fibers meeting a first predetermined specification criterion for the first multimode fiber performance parameter, and for which the at least two computed ROD slopes meet a predetermined slope criterion.
H04B 10/077 - Dispositions pour la surveillance ou le test de systèmes de transmissionDispositions pour la mesure des défauts de systèmes de transmission utilisant un signal en service utilisant un signal de surveillance ou un signal supplémentaire
G01M 11/00 - Test des appareils optiquesTest des structures ou des ouvrages par des méthodes optiques, non prévu ailleurs
A method of manufacturing an aerial micromodule cable (2) with excess length of an optical core (8) is disclosed, the cable comprising a cable jacket (3) defining a cavity (6) in which the optical core (8) is arranged, said cable having two rigid strength members (4a, 4b) embedded in the wall of the jacket (3); the method comprising guiding the cable (2) over a wheel (26); wherein a first plane (PI) intersecting the centre of gravity (CI) of the cable cavity (6) is parallel to a second plane (P2) intersecting the two rigid strength members, said first and second planes (PI, P2) being offset from each other, and wherein, during said guiding, the two rigid strength members (4a, 4b) are positioned closer to the wheel (26) than the first plane (PI) so as to cause the optical core (8) to have a core excess length of at least 0,05%.
The invention concerns a method of SZ stranding into one strand a bundle of two or more flexible micromodules, each micromodule comprising one or more optical fibers. A first pulley is located with its winding surface adjacent to a longitudinal axis of a cabling line. The bundle of micromodules is guided over the winding surface of the first pulley, the first pulley being rotating around the longitudinal axis of the cabling line. The rotational speed, or the rotational direction of the first pulley, is alternating.
G02B 6/44 - Structures mécaniques pour assurer la résistance à la traction et la protection externe des fibres, p. ex. câbles de transmission optique
D07B 3/00 - Machines ou appareillages d'application générale pour la production de cordes ou câbles retordus à partir de brins constitutifs faits de matériaux identiques ou différents
A rotary feed-through for mounting a rotating substrate tube in a lathe and providing a flow of process gas into the tube, said feed-through comprising a process gas supply line for providing a process gas into said substrate tube, a rotatable holder arranged for receiving and holding said substrate tube for rotating said substrate tube with respect to said process gas supply line, a rotary union provided between said rotatable holder and said process gas supply line for rotatably connecting said rotatable holder to said process gas supply line, a stationary housing connected to said process gas supply line and to said rotatable holder, therewith forming a closed cavity surrounding said rotary union, wherein said stationary housing further comprises an auxiliary gas supply line for providing said closed cavity with an auxiliary gas.
C03B 37/018 - Fabrication d'ébauches d'étirage de fibres ou de filaments obtenues totalement ou partiellement par des moyens chimiques par dépôt de verre sur un substrat de verre, p. ex. par dépôt chimique en phase vapeur
8.
METHOD FOR CONTROLLING ROTATION OF A WINDING SPOOL OF A PROOF-TESTING MACHINE FOR OPTICAL FIBER, CORRESPONDING SYSTEM, COMPUTER PROGRAM PRODUCT AND NON-TRANSITORY COMPUTER- READABLE CARRIER MEDIUM
The invention relates to a method for controlling rotation of a winding spool (30) onto which an optical fiber (100) is wound in a proof-testing machine, the optical fiber being guided in the proof-testing machine at a given line speed from an input pulling device (10) to an output pulling device (20), then to the spool (30), the input and output pulling device being arranged to subject the optical fiber to a predetermined tensile stress, the method comprising: upon detection of a break between an output point (A) of the input pulling device and between an input point (B) of the output pulling device, a step of controlling the rotational speed of the spool to bring it to a complete stop; - a step of passing the optical fiber between an output point (C) of the output pulling device and an input point (D) of the winding spool in a fiber accumulation zone (90) adapted to accumulate a predetermined fiber length preventing an fiber broken end resulting from the break going beyond the input point (D) of the winding spool.
B65H 51/20 - Dispositifs pour stocker temporairement le matériau filiforme pendant l'avance, p. ex. pour stockage tampon
B65H 63/036 - Dispositifs d'alarme ou de sécurité utilisés pour le déroulage, le dévidage, le défilement, l'enroulage, le bobinage ou l'emmagasinage d'un matériau filiforme, p. ex. détecteurs automatiques de défectuosités ou mécanismes d'arrêt réagissant à la réduction de tension du matériau, à l'arrêt de l'approvisionnement ou à la cassure du matériau réagissant à la rupture des matériaux caractérisés par la combinaison d'organes détecteurs ou sensibles avec d'autres dispositifs, p. ex. des dispositifs d'arrêt du mécanisme d'avancement ou d'enroulage
METHOD FOR CHARACTERIZING PERFORMANCE OF A MULTIMODE FIBER OPTICAL LINK AND CORRESPONDING METHODS FOR FABRICATING A MULTIMODE OPTICAL FIBER LINK SHOWING IMPROVED PERFORMANCE AND FOR IMPROVING PERFORMANCE OF A MULTIMODE OPTICAL FIBER LINK
The invention concerns a method of characterizing a multimode optical fiber link comprising a light source and two or more multimode fibers, which comprises: a step of characterizing each of said multimode fibers using a measurement of the Dispersion Modal Delay (DMD) for each of said multimode fibers, and delivering, for each of said multimode fibers, at least three fiber characteristic curves as a function of a radial offset value r; a step of characterizing the light source by at least three source characteristic curves showing at least three parameters of the source as a function of a fiber radius r and obtained by a technique similar to the DMD measurement; a step of computing an Effective Bandwidth (EB) of the link, comprising calculating a transfer function using both each of said source characteristic curves and each of said at least three fiber characteristic curves for each of said multimode fibers.
H04B 10/079 - Dispositions pour la surveillance ou le test de systèmes de transmissionDispositions pour la mesure des défauts de systèmes de transmission utilisant un signal en service utilisant des mesures du signal de données
10.
AN OPTICAL CABLE WITH RETRACTABLE MODULES AND A METHOD FOR PRODUCING SAID MODULES
An optical cable (1) comprises a sheath (2) surrounding a cavity (3) and a plurality of substantially parallel modules (4) arranged into said cavity (3) with a filling ratio between 20 and 50%; each of said modules (4) comprises: • four to twelve fibers (9), • A tube (5) surrounding the fibers (9) that comprises a mix of polycarbonate and a low friction polymer, chosen from the group of fluorinated polymers and polyamide; said tube (5) having a ratio between its inner di and outer do diameters between 0.45 and 0.55, and comprising an outer low friction polymer layer (6) having a thickness between 0.05 and 0.15 mm, • A filling ratio of said module 4 greater than 55%.
G02B 6/44 - Structures mécaniques pour assurer la résistance à la traction et la protection externe des fibres, p. ex. câbles de transmission optique
G02B 6/00 - Guides de lumièreDétails de structure de dispositions comprenant des guides de lumière et d'autres éléments optiques, p. ex. des moyens de couplage
11.
MULTIMODE OPTICAL FIBER WITH HIGH BANDWIDTH, AND CORRESPONDING MULTIMODE OPTICAL SYSTEM
The invention concerns a multimode optical fiber, with an ct-profile graded-index core with an a-value between 1.96 and 2.05 and a N value defined as N= (R1/λ)2(n12-n02) between 7 and 52, where R1 is the multimode core radius, n1 is the maximum index of the multimode core and n0 is the minimum index at the outer edge of the graded index core. According to the invention, a depressed region directly surrounds the graded/ index core and satisfies the criteria: -2.20 < Dn2 < 0, where Dn2 is the index difference of depressed region with external cladding, and 220 Ln(N)-1100 < V2 < 220Ln(N)-865, where V2 is the volume of the depressed region. Such a multimode fiber shows an increased OFL-bandwidth above 10000Hz.km at an operating wavelength between 950nm and 1310nm.
G02B 6/028 - Fibres optiques avec revêtement le noyau ou le revêtement ayant un indice de réfraction progressif
12.
METHOD FOR QUALIFYING THE EFFECTIVE MODAL BANDWIDTH OF A MULTIMODE FIBER OVER A WIDE WAVELENGTH RANGE FROM A SINGLE WAVELENGTH DMD MEASUREMENT AND METHOD FOR SELECTING A HIGH EFFECTIVE MODAL BANDWIDTH MULTIMODE FIBER FROM A BATCH OF MULTIMODE FIBERS
The invention relates to a method for qualifying the actual effective modal bandwidth of a multimode optical fiber over a predetermined wavelength range, comprising the steps of: carrying out (30) a Dispersion Modal Delay (DMD) measurement of the multimode optical fiber at a single wavelength to obtain an actual DMD plot; generating (32) at least two distinct modified DMD plots from the actual DMD plot, each modified DMD plot being generated by applying a temporal delay At to the recorded traces that increases in absolute values with the radial offset value roffset, each modified DMD plot being associated with a predetermined bandwidth threshold (S1; S2); for each modified DMD plot, computing (33) an effective modal bandwidth as a function of said modified DMD plot and comparing (34) the computed effective modal bandwidth (EMBc1; EMBc2) with the bandwidth threshold value to which the modified DMD plot is associated; (35) qualifying the actual effective modal bandwidth as a function of results from the comparing step.
The invention concerns a method for characterizing mode group properties of multimodal light traveling through an optical component, comprising: - providing a Mode Group Separating optical fiber in an optical path between a light source and said optical components - launching reference pulses of light with a wavelength λt from said light source through said Mode Group Separating optical fiber into said optical component at discrete intervals between a core center and a core radius of said fiber. The Mode Group Separating optical fiber is a multimode fiber with an a-profile graded index core with an α-value chosen such that said fiber satisfies the following criterion at the wavelength λt: formula (I) where: - ΔƬ is a time delay difference between consecutive mode groups; - L is a length of said fiber; - ΔTREF is a Full Width at Quarter Maximum of said reference pulses.
The invention concerns a multimode optical fiber, with a graded-index core co- doped with at least fluorine F and germanium GeO2 and a refractive index profile with at least two α-values. According to the invention, the concentration of fluorine F at the core center ([F]r=0) is between 0 and 3wt% and the concentration of fluorine F at the core outer radius ([F]r=a) is between 0.5wt% and 5.5wt%, with [F]r=a - [F]r= > 0.4wt%. For wavelengths comprised between 850nm and 1100nm, said multimode optical fiber has an overfilled launch bandwidth (OFL-BW) greater than 3500MHz.km and a calculated effective modal bandwidth (EMBc) greater than 4700MHz.km over a continuous operating wavelength range greater than 150nm.
The invention concerns a single mode optical fibre having a core and a cladding, the core refractive index profile having a trapezoid-like shape. According to an aspect of the invention, the transition part of the trapezoid-like core refractive index profile is obtained by gradually changing a concentration of at least two dopants from a concentration in said centre part of said core to a concentration in a cladding part adjacent to said core.
G02B 6/028 - Fibres optiques avec revêtement le noyau ou le revêtement ayant un indice de réfraction progressif
G02B 6/036 - Fibres optiques avec revêtement le noyau ou le revêtement comprenant des couches multiples
16.
A METHOD OF CHARACTERIZING A MULTIMODE OPTICAL FIBER LINK AND CORRESPONDING METHODS OF FABRICATING MULTIMODE OPTICAL FIBER LINKS AND OF SELECTING MULTIMODE OPTICAL FIBERS FROM A BATCH OF MULTIMODE OPTICAL FIBERS
The invention concerns a method of characterizing a multimode optical fiber link comprising a light source and a multimode fiber, which comprises: a step (170) of characterizing the multimode fiber using a measurement of the Dispersion Modal Delay (DMD) and delivering fiber characteristic data; a step (171) of characterizing the light source by at least three source characteristic curves showing three parameters of the source as a function of a fiber radius r and obtained by a technique similar to the DMD measurement; a step (173) of computing an Effective Bandwidth (EB) of the link, comprising calculating (172) a transfer function using both the fiber characteristic data and each of said source characteristic curves.
G01M 11/00 - Test des appareils optiquesTest des structures ou des ouvrages par des méthodes optiques, non prévu ailleurs
H04B 10/07 - Dispositions pour la surveillance ou le test de systèmes de transmissionDispositions pour la mesure des défauts de systèmes de transmission
17.
FEW MODE OPTICAL FIBERS FOR SPACE DIVISION MULTIPLEXING
The invention relates to an optical fiber com prising an optical core and an optical cladding surrounding the optical core, the optical core having a single α graded-index profile with α ≥ 1, and the optical core having a radius R1 and a maximal refractive index n0, said optical cladding having a refractive index nCl. Said optical cladding com prises a region of depressed refractive index ntrench, having an inner radius R2, with R2 ≥ R1, and an outer radius R3, with R3 > R2. According to embodiments of the invention, the α-value of said graded index profile and the optical core radius R1 are chosen such that R1 ≥ 13,5μm and so as to satisfy a criterion C of quality. Thus, the invention provides a few-mode optical fiber, which allow guiding an increased number of LP modes as com pared to prior art FMFs, while reaching the lowest Differential Mode Group Delay. The system reach is thus increased over prior art.
The invention relates to an optical link comprising N optical fibers, with N ≥ 2. Each optical fiber comprises an optical core and an optical cladding surrounding the optical core, the optical core having a single αi graded-index profile with αi ≥ 1, and the optical core having a radius R1i, where i E [1; N] is an index designating said optical fiber. Said optical cladding comprises a region of depressed refractive index ntrenchi, called a trench, surrounding the optical core. According to embodiments of the invention, for all optical fibers in said link, said optical core radius R1i and said length Li are chosen such that R1i ≥ 13,5μm and so as to satisfy a criterion C of quality. Thus, the invention provides a few-mode optical fiber link, which allow guiding an increased number of LP modes as compared to prior art FMF links, while reaching low Differential Mode Group Delay.
The invention relates to an optical fiber preform (20) comprising a primary preform (21) and one or more purified silica-based overclad layers (22) surrounding said primary preform (21), the purified silica-based overclad layers (22) comprising lithium and aluminium, and having a ratio between lithium concentration [Li] and aluminium concentration [Al] satisfying the following inequality (Formula (I)).
The present invention relates to a method of removing a substrate tube from the deposited layer inside of said substrate tube. In other words, the present invention relates to a method for manufacturing a precursor for a primary preform for optical fibres by means of an internal plasma deposition process,which method comprises the steps of providing a hollow substrate tube; creating a first plasma reaction zone having first reaction conditions in the interior of said hollow substrate tube by means of electromagnetic radiation for effecting the deposition of non- vitrified silica layers on the inner surface of said hollow substrate tube, and subsequently creating a second plasma reaction zone having second reaction conditions in the interior of said hollow substrate tube by means of electromagnetic radiation for effecting the deposition of vitrified silica layers on the non-vitrified silica layers deposited in the previous step; and removing the hollow substrate tube from the vitrified silica layers and the non-vitrified silica layers to obtain a deposited tube.
The invention relates to a multimode optical fiber comprising an optical core and an optical cladding surrounding the optical core, the optical core having a refractive graded- index profile, the optical cladding comprising: an inner layer surrounding said optical core, an intermediate layer, called "depressed trench", surrounding said inner layer, an outer layer surrounding said depressed trench and having a constant refractive index, said depressed trench having a width W and a negative refractive index difference Δnt with respect to the outer layer, and being designed so as to satisfy the following inequality: |0.585677 - 114.681 x S + 13.7287 x S2 + 18.7343 x S x W - 4.61112 x S x Δnt.103 - 0.913789 x W x Δnt.103| +2 x W x Δnt.103 < -30 wherein: S is the width of the inner cladding, which is comprised between 0.6 μm and 1.6 μm; Δnt is comprised between -11.10-3 and -4.10-3; W x Δnt.103 is lower than -25 μm.
It is proposed an optical fiber comprising an optical core and an optical cladding surrounding the optical core, the optical core having a refractive graded-index profile with a minimal refractive index n1 and a maximal refractive index n0, said optical fiber being such that it has a numerical aperture NA and an optical core radius a satisfying a criterion C of quality of optical communications defined by the following equation: C = NA - 0.02 x a where: Δ is the normalized refractive index difference, and in that said minimal and maximal refractive indexes nu n0 and said optical core radius « are chosen such that NA > 0.20, a > 10μm and |c| < 0.20.
An electric cable, in particular a data transmission cable, includes - at least one line (1), in particular several twisted-pair lines (P1 to P4), - a screening sheet (4.1, 4.2) for the at least one line (1) which screening sheet (4.1, 4.2) includes at least one substrate layer (20, 80) of a plastic material and at least one screening layer (30) of an electrically conductive material, in particular metal, which the substrate layer (20, 80) is lined with, wherein the screening layer (30) being provided with spacing gaps (50) for electrical interruption thereof in a longitudinal strip direction (Z), with the spacing gaps (50) extending crosswise of the longitudinal strip direction (Z) and recurring at longitudinal intervals (p), - an external envelope (7) of an insulating material,and - a semi-conductive shielding layer (6) arranged between the screening sheet (4.1, 4.2) and the external envelope (7).
The invention relates to a hybrid optical fiber that includes a multi-segmented optical core exhibiting a refractive graded-index profile typically used to support multimode transmission in which a step-index is added at the center of the optical core, the profile parameters (as) and (Δs) of this step-index being tuned so as to provide an optical fiber that transmits both error free multimode optical signals and error free single-mode optical signals. The implementation of such a refractive index profile n(r) of the optical core, as well as the choice of an adequate value of the parameters (as) and (Δs) lead to adapt the fundamental mode of the optical fiber such that the optical power coupled into the fundamental mode is maximized at the wavelength of the single-mode transmission, 1550 nm for example, while preserving a relatively reduced modal dispersion at the wavelength of the multimode transmission, 850 nm for example.
The invention relates to a hybrid optical fiber that includes a multi- segmented optical core exhibiting a refractive graded-index profile typically used to support multimode transmission in which a step-index is added at the center of the optical core, the profile parameters (as) and ( Δs ) of this step-index being tuned so as to provide an optical fiber that transmits both error free multimode optical signals and error free single-mode optical signals. The implementation of such a refractive index profile n(r) of the optical core, as well as the choice of an adequate value of the parameters (as) and ( As ) lead to adapt the fundamental mode of the optical fiber such that the optical power coupled into the fundamental mode is maximized at the wavelength of the single-mode transmission, 1550 nm for example, while preserving a relatively reduced modal dispersion at the wavelength of the multimode transmission, 850 nm for example.
The invention concerns a temperature and strain sensing optical fiber comprising a first doped radial zone (Z1) with an associated first Brillouin shift (BS1) caused by the doping of said zone (Z1) and a second doped radial zone (Z2) with associated second Brillouin shift (BS2) caused by the doping of said second zone (Z2), wherein the concentration and/or composition of the doping materials in said first and second radial zones are chosen such that the first Brillouin Shift (BS1) is different from the second Brillouin Shift (BS2) for all variations of said Brillouin Shifts (BS1, BS2) caused by temperature and/or strain.
G01K 11/32 - Mesure de la température basée sur les variations physiques ou chimiques, n'entrant pas dans les groupes , , ou utilisant des changements dans la transmittance, la diffusion ou la luminescence dans les fibres optiques
The invention concerns a cable (1) comprising a cable outer sheath (12) surrounding a cable core (11) and at least a ring (21, 23, 25, 28, 30) surrounding partly said cable outer sheath (12) so that said ring (21, 23, 25, 28, 30) presses said cable outer sheath (12) on said cable core (11) in a way adapted to increase a transfer, on said cable core (11), of a pulling effort exerted on said cable outer sheath (12).
H02G 1/08 - Méthodes ou appareils spécialement adaptés à l'installation, entretien, réparation, ou démontage des câbles ou lignes électriques pour poser les câbles, p. ex. appareils de pose sur véhicule à travers des tubes ou conduits, p. ex. tringles ou fil de tirage pour pousser ou tirer
H02G 15/007 - Dispositifs pour atténuer la contrainte mécanique
G02B 6/44 - Structures mécaniques pour assurer la résistance à la traction et la protection externe des fibres, p. ex. câbles de transmission optique
An Optical - fiber interconnect cable (10) includes one or more optical fibres (12) and one or more electrical conductors (14) surrounded by an outer jacket. The optical fibers (12), such a multimode optical fibers, are typically enclosed within a flexible polimeric tube (13) to form a flexible subunit.
The present invention relates to a UVLED apparatus for curing a coating upon a glass fiber, comprising one or more UVLED-mirror pairs, each UVLED-mirror pair comprising (i) a UVLED for emitting electromagnetic radiation and (ii) a mirror for reflecting electromagnetic radiation and a curing space in between for passage of the coated glass fiber to be cured. In addition, the present invention relates to a method to provide efficient curing of an optical-fiber coating onto a drawn glass fiber. The apparatus and method employ one or more UVLEDs that emit electromagnetic radiation into a curing space. An incompletely cured optical-fiber coating, which is formed upon a glass fiber, absorbs emitted and reflected electromagnetic radiation to effect improved curing.
C03C 25/62 - Traitement de surface des fibres ou filaments de verre, de substances minérales ou de scories par application d'énergie électrique ou ondulatoire par rayonnement particulaire ou par implantation d’ions
B05D 3/06 - Traitement préalable des surfaces sur lesquelles des liquides ou d'autres matériaux fluides doivent être appliquésTraitement ultérieur des revêtements appliqués, p. ex. traitement intermédiaire d'un revêtement déjà appliqué, pour préparer les applications ultérieures de liquides ou d'autres matériaux fluides par exposition à des rayonnements
The present invention relates to a reduced-diameter optical fiber that employs a novel coating system. When combined with a bend-insensitive glass fiber, the novel coating system according to the present invention yields an optical fiber having exceptionally low losses. The coating system features (i) a softer primary coating with excellent low- temperature characteristics to protect against microbending in any environment and in the toughest physical situations and, optionally, (ii) a colored secondary coating possessing enhanced color strength and vividness. The secondary coating provides improved ribbon characteristics for structures that are robust, yet easily entered (i.e., separated and stripped). The optional dual coating is specifically balanced for superior heat stripping in fiber ribbons, with virtually no residue left behind on the glass. This facilitates fast splicing and terminations. The improved coating system provides optical fibers that offer significant advantages for deployment in most, if not all, fϊber-to-the-premises (FTTx) systems.
G02B 1/04 - Éléments optiques caractérisés par la substance dont ils sont faitsRevêtements optiques pour éléments optiques faits de substances organiques, p. ex. plastiques
A buffered optical fiber (10) comprises a central core (11) surrounded by an optical cladding (12), a coating (13) surrounding the optical cladding, a protective buffer (15) surrounding the coating and an intermediate layer (14) between the coating 'and the protective buffer. The intermediate layer consists of hot melt seal and peel material. The intermediate layer (14) may be extruded in tandem with the outer protective buffer (15).
Disclosed is an improved, single-mode optical fiber possessing a novel coating system. When combined with a bend-insensitive glass fiber, the novel coating system according to the present invention yields an optical fiber having exceptionally low losses. The coating system features (i) a softer primary coating with excellent low-temperature characteristics to protect against microbending in any environment and in the toughest physical situations and, optionally, (U) a colored secondary coating possessing enhanced color strength and vividness. The secondary coating provides improved ribbon characteristics for structures that are robust, yet easily entered (i.e., separated and stripped). The optional dual coating is specifically balanced for superior heat stripping in fiber ribbons, with virtually no residue left behind on the glass. This facilitates fast splicing and terminations. The improved coating system provides optical fibers that offer significant advantages for deployment in most, if not all, fiber-to-the-premises (FTTx) systems.
G02B 1/04 - Éléments optiques caractérisés par la substance dont ils sont faitsRevêtements optiques pour éléments optiques faits de substances organiques, p. ex. plastiques
A multimode optical fiber comprises a central core having an alpha profile, a depressed cladding having a portion in continuity with the alpha profile of the central core and a stepped portion, and an outer cladding. The alpha profile is obtained by co-doping at least two dopants. The variation in concentration of each dopant and its derivative in relation to the fiber radius are continuous. A multimode fiber for Ethernet optical system with an improved bandwidth is thus obtained.
A method for manufacturing an optical fiber preform comprising a step of providing a primary preform forming a core and an inner cladding, and a step of overcladding said primary preform by projecting silica grain under a plasma torch on the primary preform and vitrifying said silica grain on the periphery of said primary preform in order to form an overcladding layer, wherein an alkali material is projected together with the silica grain during the overcladding step which alkali material is incorporated in the overcladding layer.
A cable, provided with at least one signal conductor (5), for instance glass fiber and/or glass fiber bundle, received in a cable inner space (3), such that a signal conductor take -out part can be taken out of the cable inner space (3), wherein the length of said take-out part is at least 1% of a cable length over which the take-out part can be taken out of the cable, preferably more than 2%, in particular more than 4% and more in particular more than 10%.
A cable, comprising a cylindrical cable wall (2) surrounding a hollow cable inner space (3), wherein the cable (1) is provided with at least one signal conductor (5), for instance glass fiber and/or glass fiber bundle, wherein, in a first position, the signal conductor (5) extends substantially in the cable inner space (3) and over a particular distance along the cable wall (2), along an at least partly curved path, such that a length of the signal conductor (5) is larger than a length of the cable wall (2).
This invention relates to a system and method for providing a buffer tube and, more particularly, to a system and method for providing a buffer tube that includes a jet that jets fluid against a buffer tube coating. The system includes a crosshead that coats at least one optical fiber with a buffer tube coating; a vat that includes a fluid, the fluid within the vat cooling the buffer tube coating to form a buffer tube, and the vat being provided downstream of the crosshead; a pulling roller that pulls the cooled buffer tube, the pulling roller being provided downstream of the vat; and a jet provided within the vat. The jet jets a jetting fluid against the buffer tube coating so as to compress the buffer tube coating in a region downstream of the jet.
The present invention relates to loose tube optical waveguide fiber assembly which is optimized for easy and fast installation as plenum cable, e.g. in customer premises for FTTH (fiber to the home) applications. One of the objects of the present invention is to provide a loose tube optical waveguide fiber assembly which is suitable for fixed in-house cabling and comprises extremely low-cost for a large- scale installation of FTTH
The present invention relates to a loose tube optical waveguide fiber assembly which is suitable for riser or plenum applications, comprising (a) one or more optical waveguides, and (b) a protective tube loosely surrounding said one or more optical waveguides, said tube comprising an inner surface and an outer surface, said assembly containing no gel-like compounds, and (c) one or more strengthening members being disposed between the inner surface of the protective tube and the outer surface of the protective tube as one or more longitudinal strengthening elements or as a layer of strengthening element.
The invention relates to the field of optical fiber cables and more specifically to an optical fiber cable especially suited for blown installation or pushing installation in microducts of small diameter. The microcable comprises a protective sheath holding a plurality of optical fibers, wherein said protective sheath is composed of two layers of different synthetic materials, in which the inner layer of said protective sheath consists of a material having an elasticity modulus in a range of 1500-3000 MPa at room temperature, and that the outer layer of said protective sheath consists of a material having an elasticity modulus in the range of 600-1200 MPa at room temperature.
The invention relates to the field of optical fiber cables and more specifically to an optical fiber cable especially suited for blown installation or pushing installation in microducts of small diameter. A microcable for installation in small microducts comprising an outer sheath as buffer tube holding a plurality of optical fibers without a layer of strength elements stranded around said outer sheath, has an outer sheath made of one single thermoplastic material.
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