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.