An anti-torsion solid-core polarization-maintaining photonic crystal fiber includes a cladding having an inner layer arranged around the core and an outer layer between the inner layer and the outer wall of the cladding. The inner layer has multi-layer air holes used to construct optical properties and two micron-size air holes arranged along the x-axis extending in the center producing form birefringence. The outer layer includes multi-layer air holes arranged radially along the y-axis. The size and arrangement of the multi-layer air holes in the outer layer cause the bending stiffness of the photonic crystal fiber along the x-axis to be different from that along the y-axis. While meeting the requirements of the optical properties of the fiber, the photonic crystal fiber possesses an anti-torsion ability due to the anisotropy of stress distribution in the radial direction, thereby reducing the non-reciprocal phase difference generated by the magneto-optic Faraday Effect.

An optical fiber having an axial direction and a cross section perpendicular to the axial direction, and a method and preform for producing such an optical fiber. The optical fiber is adapted to guide light at a wavelength λ, and includes a core region, an inner cladding region surrounding said core region, and at least one of a first type of feature including a void and a surrounding first silica material. The core, the inner cladding region and the first type of feature extends along said axial direction over at least a part of the length of the optical fiber. The first silica material has a first chlorine concentration of about 300 ppm or less.

A microstructured optical fiber having a length and a longitudinal axis along its length, the finer including a core region capable of guiding light along the longitudinal axis and a cladding region which surrounds the core region, the cladding region comprising a cladding background material and a plurality of cladding features within the cladding background material, the cladding features being arranged around the core region, wherein the cladding region comprises an inner cladding region comprising an innermost ring of cladding features and an outer cladding region comprises outer cladding rings of outer cladding features, the innermost ring consisting of those cladding features being closest to the core region, wherein the rings of cladding features each comprise bridges of cladding background material separating adjacent features of the ring, wherein the bridges of the innermost ring have an average minimum width (w1), the minimum width of a bridge of a ring being the shortest distance between two adjacent features of the ring; and wherein at least one outer cladding ring has an average minimum width (w2) of bridges that is larger than the average minimum width (w1) of the bridges of the innermost ring. Also described are a cascade optical fiber with at least one fiber as described, as well as a source of supercontinuum radiation.

A nested anti-resonant nodeless hollow core fiber (NANF) enables transmission of multi-kilowatt, continuous wave (CW) light beams operating in wavelengths between 1050 nm and 1100 nm provided by single mode lasers. Such a NANF has little loss over kilometer ranges, and can be employed in long distance subsurface applications, such as in the petroleum industry.

A hollow core optical fibre comprises a tubular jacket; a cladding comprising a plurality of primary capillaries spaced apart from one another in a ring and each bonded to an inner surface of the jacket at a peripheral location around the circumference of the jacket; and a hollow core formed by a central void within the ring of primary capillaries; wherein the cladding further comprises, within each primary capillary, two secondary capillaries and no more, the two secondary capillaries spaced apart from one another and each bonded to an inner surface of the primary capillary at an azimuthal location around the circumference of the primary capillary which is displaced from the peripheral location of the primary capillary.

A microstructured optical fiber including a core region and a cladding region which surrounds the core region. The cladding region includes a plurality of cladding features within a cladding background material, wherein the cladding region includes an inner cladding region with at least one inner ring of cladding features and an outer cladding region with at least three outer cladding rings of outer cladding features. The inner cladding features have a first characteristic diameter and the outer cladding region includes a plurality of outer cladding features having a characteristic diameter smaller than the first characteristic diameter. The first characteristic diameter is at least about 10% larger than an average diameter of the outer cladding features and the core region has a diameter of at least about 2 μm. A cascade optical fiber with at least one fiber as described, as well as a source of optical supercontinuum generation.

A polarization-maintaining dispersion-compensation microstructure fiber includes an inner core, an air-hole array in area 1 and an air-hole array in area 2. The air holes in the area 1 and 2 air-hole arrays are arranged in square lattice. The air-hole arrays in areas 1 and 2 are dislocated by half-layer along y-direction. In area 1, 2 air holes in the middle row are omitted to form a solid area as the inner core. 2 outer cores are located in 2 sub-areas of area 2, and each outer core contains 2 air holes. The long (or short) axes of the inner and outer cores are perpendicular, and the center points of the inner core and the two outer cores are located on the x-axis. The optical mode has a large negative dispersion in a certain polarized direction of the inner core, and the microstructure fiber can maintain the polarized direction of this mode during transmission.

A broadband light source device for creating broadband light pulses includes a hollow-core fiber and a pump laser source device. The hollow-core fiber is configured to create the broadband light pulses by an optical non-linear broadening of pump laser pulses. The hollow-core fiber includes a filling gas, an axial hollow light guiding fiber core configured to support core modes of a guided light field, and an inner fiber structure surrounding the fiber core and configured to support transverse wall modes of the guided light field. The pump laser source device is configured to create and provide the pump laser pulses at an input side of the hollow-core fiber. The transverse wall modes include a fundamental transverse wall mode and second and higher order transverse wall modes.

Disclosed is a Chinese knot-like porous fiber core ultra-high birefringence THz optical fiber. The optical fiber comprises a substrate, claddings and fiber cores, wherein the claddings and the fiber cores are arranged in the substrate, and the fiber cores are embedded in the centers of the claddings; and the fiber core comprises a first fiber core region, a second fiber core region and a third fiber core region, the center of the first fiber core region 4 serves as the origin of coordinates, and the first fiber core region 4 is composed of six regular hexagon units with overlapped boundaries in the x-axis direction. In the present disclosure, the fiber core comprises a first fiber core region, a second fiber core region and a third fiber core region, and the three regions jointly form a fiber core region of a Chinese knot-like porous fiber core.

The invention concerns 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 comprises a core extending along the length of said longitudinal axis and a cladding region surrounding the core. At least the cladding region comprises 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 comprises hydrogen and/or deuterium. In at least the degradation resistant length section the PCF further comprises a main coating surrounding the cladding region, which main coating is hermetic for the hydrogen and/or deuterium at a temperature below Th, wherein Th is at least about 50° C., preferably 50° C.<Th<250° C.