Abstract: An article comprising an optical fiber, the fiber comprising at least one core surrounded by a first outer cladding region, the first outer cladding region being surrounded by a second outer cladding region, the first outer cladding region in the cross-section comprising a number of first outer cladding features having a lower refractive index than any material surrounding the first outer cladding features, wherein for a plurality of said first outer cladding features, the minimum distance between two nearest neighboring first outer cladding features is smaller than 1.0 ?m or smaller than an optical wavelength of light guided through the fiber when in use; a method of its production, and use thereof.

Abstract: A mircrostructured optical fiber that guides light in a core region, where the fiber has a cladding region that includes a background material and a number of cladding features or elements that are elongated in the longitudinal direction of the fiber and have a higher refractive index than the cladding background material. The core region has a lower effective refractive index than the cladding, and the fiber may guide light in the core by photonic bandgap effects.

Abstract: An optical fiber for transmitting light, said optical fiber having an axial direction and a cross section perpendicular to said axial direction, said optical fiber comprising: (1) a first core region comprising a first core material having a refractive index Nco,1; (2) a microstructured first cladding region surrounding the first core region, said first cladding region comprising a first cladding material and a plurality of spaced apart first cladding features or elements that are elongated in the fiber axial direction and disposed in the first cladding material, said first cladding material having a refractive index Ncl,1 and each said first cladding feature or element having a refractive index being lower than Ncl,1, whereby a resultant geometrical index Nge,cl, 1? of the first cladding region is lowered compared to Ncl,1; (3) a second core region surrounding said first cladding region, said second core region comprising a second core material having a refractive index Nco,2, and (4) a second cladding regio

Abstract: An optical wavelength conversion device including a micro-structured optical waveguide, which includes sections with a non-linear material having an index of refraction which changes as a non-linear function of light intensity. The optical waveguide includes a light guiding core region, and is dimensioned for providing spatial overlap between the sections filled with the non-linear material and light propagating within the waveguide. First and second optical light sources may also be included, the second light source having an intensity sufficient to change the refractive index of the non-linear material sufficiently to encode or modulate the light from the first light source through the effect of leaking light from the first light source inside the guiding core to the outside of the guiding core.

Abstract: A microstructured fiber having a cladding comprising a number of elongated features that are arranged to provide concentric circular or polygonial regions surrounding the fiber core. The cladding comprises a plurality of concentric cladding regions, at least some of which comprising cladding features. Cladding regions comprising cladding features of a relatively low index type are arranged alternatingly with cladding regions of a relatively high index type. The cladding features are arranged in a non-periodic manner when viewed in a cross section of the fiber. The cladding enables waveguidance by photonic bandgap effects in the fiber core. An optical fiber of this type may be used for light guidance in hollow core fibers for high power transmission. The special cladding structure may also provide strong positive or negative dispersion of light guided through the fiber-making the fiber useful for telecommunication applications.

Abstract: A microstructured optical fiber having a specially designed cladding to provide single mode waveguidance and low sensitivity to bending losses. In one aspect the optical fiber has an inner and an outer cladding each comprising elongated features. The inner cladding features have normalized dimensions in the range from 0.35 to 0.50 and the outer cladding features have normalized dimensions in the range from 0.5 to 0.9, where the normalization factor is a typical feature spacing. The fiber is further characterized by a feature spacing of the inner cladding larger than 2.0 micron. In a second aspect, the fiber has a special non-circular and non-equilateral-polygonial outer cross-sectional shape to mechanically ensure bending in predetermined directions that are favourable with respect to low bending losses.

Abstract: An optical fiber having a periodical cladding structure providing an photonic band gap structure with superior qualities. The periodical structure being one wherein high index areas are defined and wherein these are separated using a number of methods. One such method is the introduction of additional low index elements, another method is providing elongated elements deformed in relation to a circular cross section. Also described is a cladding structure comprising elongated elements of a material having an index of refraction higher than that of the material adjacent thereto. Using this additional material, prior art structures may obtain much better qualities.

Abstract: The present invention relates to optical fibers and especially to optical fibers having microstructures in core and/or cladding region(s). The fibers may be utilized for dispersion compensation and non-linear applications.

Abstract: An object of the present invention is to provide new designs of microstructured optical fibres that may be fabricated without use of voids, such as fibres being realized using silica and silica doping techniques. The invention relates to a mircrostructured optical fibre that guides light in a core region (52), where the fibre has a cladding region that comprises a background material (51) and a number of cladding features or elements (50) that are elongated in the longitudinal direction of the fibre and have a higher refractive index than the cladding background material. The core region has a lower effective refractive index than the cladding, and the fibre may guide light in the core by photonic bandgap effects. The present invention provides designs of photonic bandgap fibres that may operate without the use of voids in the cladding, thereby simplifiying fabrication of photonic bandgap fibres compared to prior art.

Abstract: In accordance with the invention there is provided an optical wavelength conversion device. The conversion device comprises a micro-structured optical waveguide, which includes sections with a non-linear material having an index of refraction which changes as a non-linear function of light intensity. The optical waveguide includes a light guiding core region, and the waveguide is dimensioned for providing spatial overlap between the sections filled with the non-linear material and light propagating within the waveguide. The conversion device further comprises a first optical light source for introducing light into the waveguide in a mode guided along the core, and a second intensity modulated light source for introducing encoding light into the waveguide in such a manner that it illuminates the sections filled with a non-linear material.

Abstract: A microstructured fiber having a cladding comprising a number of elongated features that are arranged to provide concentric circular or polygonial regions surrounding the fibre core. The cladding comprises a plurality of concentric cladding regions, at least some of which comprising cladding features. Cladding regions comprising cladding features of a relatively low index type are arranged alternatingly with cladding regions of a relatively high index type. The cladding features are arranged in a non-periodic manner when viewed in a cross section of the fiber. The cladding enables waveguidance by photonic bandgap effects in the fiber core. An optical fiber of this type may be used for light guidance in hollow core fibers for high power transmission. The special cladding structure may also provide strong positive or negative dispersion of light guided through the fibre-making the fibre useful for telecommunication applications.

Abstract: A microstructured optical fibre having a specially designed cladding to provide single mode waveguidance and low sensitivity to bending losses. In one aspect the optical fibre has an inner and an outer cladding each comprising elongated features. The inner cladding features have normalized dimensions in the range from 0.35 to 0.50 and the outer cladding features have normalized dimensions in the range from 0.5 to 0.9, where the normalization factor is a typical feature spacing. THe fibre is further characterized by a feature spacing of the inner cladding larger than 2.0 micron. In a second aspect, the fibre has a special non-circular and non-equilateral-polygonial outer cross-sectional shape to mechanically ensure bending in predetermined directions that are favourable with respect to low bending losses.

Abstract: An article comprising an optical fiber, the fiber comprising at least one core surrounded by a first outer cladding region, the first outer cladding region being surrounded by a second outer cladding region, the first outer cladding region in the cross-section comprising a number of first outer cladding features having a lower refractive index than any material surrounding the first outer cladding features, wherein for a plurality of said first outer cladding features, the minimum distance between two nearest neighboring first outer cladding features is smaller than 1.0 &mgr;m or smaller than an optical wavelength of light guided through the fiber when in use; a method of its production, and use thereof.

Abstract: A micro-structured optical fibre having a cladding comprising a number of elements having a non-circular cross-section. Each element has at least one part extending outside a circle having the same cross-sectional area as the element. These extending parts are directed in the same direction. This cladding structure provides polarization preserving properties to the optical fibre. Optical fibers using this technology may have claddings with elements placed non-periodically as well as in a two-dimensional periodic lattice-such as cladding providing Photonic Band Gap (PGB) effects.

Abstract: The present invention relates to a new class of optical waveguides, in which waveguiding along one or more core regions is obtained through the application of the Photonic Bandgap (PBG) effect. The invention further relates to optimised two-dimensional lattice structures capable of providing complete PBGs, which reflects light incident from air or vacuum. Such structures may be used as cladding structures in optical fibers, where light is confined and thereby guided in a hollow core region. In addition, the present invention relates to designs for ultra low-loss PBG waveguiding structures, which are easy to manufacture. Finally, the present invention relates to a new fabrication technique, which allows easy manufacturing of preforms for photonic crystal fibers with large void filling fractions, as well as it allows a high flexibility in the design of the cladding and core structures.

Abstract: A micro-structured optical fibre having a cladding comprising a number of elements having a non-circular cross-section. Each element has at least one part extending outside a circle having the same cross-sectional area as the element. These extending parts are directed in the same direction. This cladding structure provides polarisation preserving properties to the optical fibre. Optical fibres using this technology may have claddings with elements placed non-periodically as well as in a two-dimensional periodic lattice-such as cladding providing Photonic Band Gap (PGB) effects.

Abstract: Micro-structured optical fibers are improved with respect to increasing the dispersion, both to large negative or large positive values, in a first fiber design in which the fiber has a micro-structured core region being surrounded by a micro-structured cladding region with cladding features being large compared to a predetermined wavelength of light, which can be guided through the fiber. Preferably, the effective index of refraction of the core region, Nco, is larger than the effective index of refraction of the cladding region, Ncl, at the predetermined wavelength of light. It is further preferred that the refractive index of one or more of the core features is lower than the refractive index of the core material.