Abstract:
A hollow core fiber has a cladding comprising a matrix of cells, wherein each cell comprises a hole and a wall surrounding the hole. The fiber further has a hollow core region comprising a core gap in the matrix of cells, wherein the core gap spans a plurality of cells and has a boundary defined by the interface of the core gap. The matrix of cells comprises a plurality of lattice cells, and a plurality of defect cells characterized by at least one difference in at least one property from that of the lattice cells. The cells at the core region boundary include lattice cells and defect cells that are arranged in a pattern that define two orthogonal axes of reflection symmetry, so as to produce birefringence in a light propagating through the hollow core fiber.
Abstract:
An optical fiber that includes a central core (34) having a maximum dimension (A) greater than a minimum dimension (B), preferably with an aspect ratio greater than 1.5, the fiber having at least one air hole (24, 26) positioned on opposite sides of the central core and extending along the fiber's length wherein the fiber supports a single polarization mode within an operating wavelength band. The fiber may be coupled to optical components in systems to provide single polarization in the band. A method for manufacturing the fiber is also provided.
Abstract:
Microstructured optical fibre is fabricated using extrusion. The main design of optical fibre has a core suspended in an outer wall by a plurality of struts. A specially designed extruder die is used which comprises a central feed channel, flow diversion channels arranged to divert material radially outwards into a welding chamber formed within the die, a core forming conduit arranged to receive material by direct onward passage from the central feed channel, and a nozzle having an outer part in flow communication with the welding chamber and an inner part in flow communication with the core forming conduit, to respectively define an outer wall and core of the preform. With this design a relatively thick outer wall can be combined with thin struts (to ensure extinction of the optical mode field) and a core of any desired diameter or other thickness dimension in the case of non-circular cores. As well as glass, the extrusion process is suitable for use with polymers. The microstructured optical fibre is considered to have many potential device applications, in particular for non-linear devices, lasers and amplifiers.
Abstract:
The core of a fiber (115) is controlled during production. A rod (116) presses on the molten core glass (110). A sensor (126) senses the diameter of the fiber (115). A controller (120) controls the draw speed and a rod control device (122).
Abstract:
L'invention concerne un produit d'isolation thermique à base de laine minérale comprenant des fibres minérales, le produit comportant deux faces principales et des bords longitudinaux et transversaux perpendiculaires aux faces principales, le produit étant caractérisé par les taux d'orientation suivants: -un taux d'orientation longitudinal supérieur ou égal à 48%, voire à 50%, selon un angle de plus ou moins 6° par rapport au plan des faces principales, lorsque les fibres minérales sont comptabilisées seulement en coupe longitudinale, et -un taux d'orientation moyen supérieur ou égal à 40%, voire à 45%, selon un angle de plus ou moins 6° par rapport au plan des faces principales, lorsque les fibres minérales sont comptabilisées à la fois en coupe transversale et en coupe longitudinale. L'invention permet d'améliorer le pouvoir isolant d'un produit d'isolation thermique à base de laine minérale sans augmenter son épaisseur.
Abstract:
A method of fabricating a photonic crystal or photonic band gap optical fiber comprises providing a preform that includes a plurality of holes in an outer diameter, wherein the holes extend from a first end of a preform to a second end of the preform, and forming at least one radially inwardly-extending slot within the preform such that the slot intersects at least some of the holes, wherein the slot does not intersect at least one hole. The method also includes establishing a first pressure in the holes intersected by the slot by introducing the first pressure to the slot, and establishing a second pressure in the at least one hole not intersected by the slot by introducing the second pressure to an end of the at least one hole not intersected by the slot. The method further includes drawing the preform into a fiber while independently controlling the first and second pressures.
Abstract:
An optical fiber including: (i) a silica based, rare earth doped core (12) having a first index of refraction n 1 ; (ii) a silica based inner cladding (14) surrounding the core and having a second index of refraction n 2 , such that n 1 >n 2 , the inner cladding having a plurality of air holes (24, 26) extending longitudinally through the length of the optical fiber; (iii) a silica based outer cladding (16) surrounding the inner cladding and having a third index of refraction n 3 , such that n 2 >n 3 ; wherein the optical fiber supports a single polarization mode within the operating wavelength range.
Abstract:
A photonic band gap fiber and method of making thereof is provided. The fiber is made of a non-silica-based glass and has a longitudinal central opening, a microstructured region having a plurality of longitudinal surrounding openings, and a jacket. The air fill fraction of the microstructured region is at least about 40%. The fiber may be made by drawing a preform into a fiber, while applying gas pressure to the microstructured region. The air fill fraction of the microstructured region is changed during the drawing.
Abstract:
A hole-assisted fiber comprises a core region and a cladding region, where the cladding region includes multiple substantially elliptical holes spaced apart from each other to surround the core region. The holes are filled with one of a gas and a liquid to form a low refractive index portion of the cladding region. In addition, a method of fabricating a hole assisted fiber includes forming one or more slots in the perimeter of the cladding region. A tube is overcollapsed around the perimeter of the cladding region to form one or more channels, where the one or more channels bounded on one side by the overcollapsed tube. A fiber is drawn from the overcollapsed preform. An internal pressure is applied to the one or more channels during the fiber drawing step to form one or more holes of a pre-selected shape within the cladding region.
Abstract:
A method of drawing an optical fibre (310') or the like from an elongate pre-form (310), the fibre (310') and the pre-form (310) having at least one hole (311,312) running along their lengths, includes the steps of heating the pre-form (310) and drawing the fibre (310') from the pre-form (310) while controlling the ambient pressure around the pre-form (310) to be significantly higher or significantly lower than it would be under standard fibre drawing conditions.