Abstract: A method of manufacturing a microstructured fiber, includes: providing a preform having a plurality of elongate holes; mating at least one, but not all, of the holes with a connector to connect the hole(s) to an external pressure-controller; drawing the preform into the fiber while controlling gas pressure in the hole(s) connected to the pressure-controller.

Abstract: A method of manufacturing a microstructured fibre, includes: providing a preform having a plurality of elongate holes; mating at least one, but not all, of the holes with a connector to connect the hole(s) to an external pressure-controller; drawing the preform into the fibre whilst controlling gas pressure in the hole(s) connected to the pressure-controller.

Abstract: An optical fiber having a cladding region surrounding a core region having an elongate core hole, the inner or outer surface of the core hole having a surface roughness with a spatial period equal to or less than 5 ?m by a spectral power below 0.0017 nm2 ?m?1. A method of making an optical fiber including a cladding region having an arrangement of elongate cladding holes in a matrix material, surrounding an elongate core region having an elongate core hole, the method including the step of increasing the surface tension of the matrix material prior to or during the step of heating and drawing the fiber.

Abstract: Novel preforms and methods of making novel preforms are described. The preforms are suitable for being drawn into photonic bandgap optical fibres. In one form, the preform comprises a stack of elongate members having, in transverse cross section, a triangular close-packed arrangement of circular cross section capillaries, which define interstitial regions containing solid rods. The stack is supported around a relatively large capillary, which defines an inner region of the stack. The stack may be adapted by varying the number of rods in any given interstitial region, in order to generate various different configurations of cladding structure, which can be made into optical fibres having surprising operational characteristics, such as a split gap.

Abstract: A photonic optical fiber and method of making the optical fiber. The method includes assembling a plurality of elongate elements to define an elongate void; forming within the void a material contacting at least some of the elements while maintaining the elongate void; and drawing a preform, including the assembly of elongate elements, into an optical fiber.

Abstract: A holey optical fibre for supporting propagation of light of a wavelength ?,comprises a plurality of cylinders (10) each having a longitudinal axis, the cylinders (10) being separated from each other by regions of a matrix material (20) and having their longitudinal axes substantially parallel to each other. Each cylinder (10) has a diameter, in the plane perpendicular to the longitudinal axis, that is small enough for the composite material of the ensemble of cylinders and matrix material to be substantially optically homogenous in respect of light of wavelength ?.

Abstract: A method of joining a first optical fiber (110) to a second optical fiber (130) comprises the steps of: (i) providing a preform element (10) comprising material defining a primary elongate cavity (40); (ii) inserting the first optical fiber (110) into the primary cavity (40) to form a preform (125); and (iii) drawing the second optical fiber (130) from the preform (125); wherein, the second optical fiber (130) includes a core region comprising material that has been drawn from the first optical fiber (110).

Abstract: A photonic crystal fiber comprising a bulk material having an arrangement of longitudinal holes, the fiber including a cladding region and a guiding core (280), the cladding region having an effective-refractive-index which varies across the fiber's cross section, wherein, in use, the effective-refractive-index variation causes light propagating in the fiber to have a different transverse profile from the profile that it would have if the cladding region were of a substantially uniform effective refractive index.

Abstract: A photonic crystal fiber comprising: a core (20) having a refractive index; and a cladding region (10) at least substantially surrounding the core (20) and comprising a bulk material having a second refractive index that is higher that the first refractive index, the bulk material containing an arrangement of elongate, longitudinal holes that comprise hole material of a third refractive index that is lower than the first refractive index; such that an electromagnetic mode guided in the core (20) has an evanescent wave that becomes more closely confined to the vicinity of the core (20) as the wavelength of the electromagnetic mode is increased over a first range of wavelengths.

Abstract: A method of joining a first optical fibre (110) to a second optical fibre (130) comprises the steps of: (i) providing a preform element (10) comprising material defining a primary elongate cavity (40); (ii) inserting the first optical fibre (110) into the primary cavity (40) to form a preform (125); and (iii) drawing the second optical fibre (130) from the preform (125); wherein, the second optical fibre (130) includes a core region comprising material that has been drawn from the first optical fibre (110).

Abstract: A holey optical fibre for supporting propagation of light of a wavelength &lgr;,comprises a plurality of cylinders (10) each having a longitudinal axis, the cylinders (10) being separated from each other by regions of a matrix material (20) and having their longitudinal axes substantially parallel to each other. Each cylinder (10) has a diameter, in the plane perpendicular to the longitudinal axis, that is small enough for the composite material of the ensemble of cylinders and matrix material to be substantially optically homogenous in respect of light of wavelength &lgr;.

Abstract: A photonic-crystal fibre comprises a core (20) and a cladding (10) with longitudinal holes. The refractive index of the core is lower than that of the cladding bulk material, e.g. by fluorine doping of the core material. The holes are air-filled cavities extending along the longitudinal direction of the fibre. One property of the fibre is that a guided mode having longer wavelength is more confined in the core than a mode with a shorter wavelength. Such a fibre may have a cut-off wavelength &lgr;c? such that the fibre is unable to guide in its core light of wavelengths shorter than &lgr;c.

Abstract: A photonic crystal fibre comprising a bulk material having an arrangement of longitudinal holes, the fibre including a cladding region and a guiding core (280), the cladding region having an effective-refractive-index which varies across the fibre's cross section, wherein, in use, the effective-refractive-index variation causes light propagating in the fibre to have a different transverse profile from the profile that it would have if the cladding region were of a substantially uniform effective refractive index.

Abstract: A composite material for supporting propagation of light of a wavelength &lgr;, comprising a plurality of cylinders each having a longitudinal axis, the cylinders being separated from each other by regions of a matrix material and the cylinders having their longitudinal axes substantially parallel to each other, and each cylinder having a diameter, in the plane perpendicular to the longitudinal axis, that is small enough for the composite material to be substantially optically homogeneous in respect of light of wavelength &lgr;.