This disclosure relates to an MCF fiber being usable for short-haul O-band transmission, having a standard coating diameter in an MFD almost the same as that of a general-purpose SMF, being capable of splicing fibers without either a marker or a polarity, and including 12 cores usable for counter propagation. The MCF includes 12 cores and a common cladding, and the common cladding has an outer periphery with a circular cross-section, the 12 cores are arranged such that no adjacent relationship is established between cores each having an adjacent relationship with any core, and are arranged such that centers of the 12 cores are line symmetric with respect to an axis as a symmetry axis that intersects with the central axis and that passes through none of the centers of the 12 cores, and an arrangement of the centers of the 12 cores has rotational symmetry once.

An optical fibre assembly comprises a hollow core optical waveguide comprising a hollow core surrounded by a structured arrangement of longitudinally extending capillaries providing an inner cladding surrounded by an outer cladding; a diagnostic solid core optical waveguide comprising a solid core surrounded by a cladding, and extending substantially parallel to the hollow core optical waveguide; and a jacket surrounding both the hollow core optical waveguide and the solid core optical waveguide and forming a common mechanical environment for the hollow core optical waveguide and the solid core optical waveguide. The optical fibre assembly may be or may comprise or be included in an optical fibre cable, and may be used in a method for testing hollow core optical waveguides.

A gas pressure maintaining and adjusting device, a microstructure optical fiber and a preparation method of the microstructure optical fiber belong to the field of preparation of special optical fibers. In the gas maintaining and adjusting device, a communication control module is electrically connected with a main console of an optical fiber drawing tower; a signal output end of the communication control module is connected with a signal receiving end of a programmable logic controller (PLC); the PLC is provided with a gas pressure threshold display screen; the signal receiving end of the PLC is further connected with a signal output end of a pressure controller; and the PLC is further connected with an electromagnetic valve used for controlling opening and closing of a gas inlet and a gas outlet.

A Photonic Crystal Fiber (PCF) a method of its production and a supercontinuum light source comprising such PCF. The PCF has a longitudinal axis and includes a core extending along the length of said longitudinal axis and a cladding region surrounding the core. At least the cladding region includes a plurality of microstructures in the form of inclusions extending along the longitudinal axis of the PCF in at least a microstructured length section. In at least a degradation resistant length section of the microstructured length section the PCF includes hydrogen and/or deuterium. In at least the degradation resistant length section the PCF further includes a main coating surrounding the cladding region, which main coating is hermetic for the hydrogen and/or deuterium at a temperature below T.sub.h, wherein T.sub.h is at least about 50° C., preferably 50° C.<T.sub.h<250° C.

A terahertz waveguide includes an input segment, a transmission segment and an output segment. The input segment includes an input waveguide and an input microstructured waveguide. One end of the input waveguide is connected with one end of the core of the input microstructured waveguide. The transmission segment includes at least a sub-wavelength waveguide, an air cladding surrounding the sub-wavelength waveguide and a solid outer cladding surrounding the air cladding. The other end of the core of the input microstructured waveguide is connected with one end of the sub-wavelength waveguide. The other end of the sub-wavelength waveguide is connected with the core of the output microstructured waveguide. One end of the solid outer cladding is connected with the cladding of the input microstructured waveguide, and an output segment. The output segment includes an output microstructured waveguide and an output waveguide.

The invention comprises a delivery fiber assembly suitable for delivering broad band light. The delivery fiber assembly comprises a delivery fiber and a connector member. The deliver has a length, an input end for launching light and a delivery end for delivering light, where the delivery fiber comprises along its length a core region and a cladding region surrounding the core region. The cladding region comprises a cladding background material having a refractive index N.sub.bg and a plurality of inclusions of solid material having refractive index up to N.sub.inc and extending in the length of the longitudinal axis of the delivery fiber, wherein N.sub.inc<N.sub.bg and the plurality of inclusions in the cladding region is arranged in a cross-sectional pattern comprising at least two rings of inclusions surrounding the core region. The connector is mounted to the delivery fiber at a delivery end section of the delivery fiber comprising said delivery end. The delivery fiber has a transmission bandwidth of about 200 nm or more, such as of about 300 nm or more, such as of about 400 nm or more, such as of about 500 nm or more.

A terahertz waveguide includes an input segment, a transmission segment and an output segment. The input segment includes an input waveguide and an input microstructured waveguide. One end of the input waveguide is connected with one end of the core of the input microstructured waveguide. The transmission segment includes at least a sub-wavelength waveguide, an air cladding surrounding the sub-wavelength waveguide and a solid outer cladding surrounding the air cladding. The other end of the core of the input microstructured waveguide is connected with one end of the sub-wavelength waveguide. The other end of the sub-wavelength waveguide is connected with the core of the output microstructured waveguide. One end of the solid outer cladding is connected with the cladding of the input microstructured waveguide, and an output segment. The output segment includes an output microstructured waveguide and an output waveguide.

A method of processing by controlling one or more beam characteristics of an optical beam may include: launching the optical beam into a first length of fiber having a first refractive-index profile (RIP); coupling the optical beam from the first length of fiber into a second length of fiber having a second RIP and one or more confinement regions; modifying the one or more beam characteristics of the optical beam in the first length of fiber, in the second length of fiber, or in the first and second lengths of fiber; confining the modified one or more beam characteristics of the optical beam within the one or more confinement regions of the second length of fiber; and/or generating an output beam, having the modified one or more beam characteristics of the optical beam, from the second length of fiber. The first RIP may differ from the second RIP.

Described are optical fibers and scanning fiber displays comprising optical fibers. The disclosed optical fibers include a plurality of mass adjustment regions, such as gas-filled regions, positioned between a central waveguiding element and an outer periphery for reducing a mass of the optical fiber as compared to an optical fiber lacking the plurality of mass adjustment regions.

An optical fibre for an ultrafast laser endoscope including at least the following structures: a hollow core, the periphery of which has an order of symmetry of at least six when considering axes of symmetry passing through the centre of the core and through the centre of convex shapes, seen from the centre of the core, the convex shapes at least partly making up the periphery of the core; an intermediate layer of cellular structure surrounding the core; a light conducting peripheral structure surrounding the intermediate layer of cellular structure; and an outer sheath surrounding the light-conducting peripheral structure. A particular advantage of the optical fibre is that it optimizes the emission of a high-power flux associated with fluorescence collection.