A photonic crystal fiber according to the present invention has a plurality of holes arranged in the optical fiber along a longitudinal direction, in which the holes are arranged such that, in a cross section, a hole ratio which is an area of the holes per unit area is larger in a central side than in an outer side in a portion corresponding to a cladding and that a wide core area can be obtained while the number of modes that can be propagated is limited to several. Moreover, in a high-power optical transmission system according to the present invention, the amount of axis misalignment between the central axis of a laser oscillator and the central axis of the photonic crystal fiber is less than or equal to a certain amount.

A hollow-core optical fiber may include a hollow-core extending along a central longitudinal axis of the hollow-core optical fiber; a substrate; a first cladding positioned between the central longitudinal axis and an inner surface of the substrate, the first cladding surrounding the central longitudinal axis of the hollow-core optical fiber and having a Bragg structure configured to provide a photonic bandgap operable to confine an optical signal with a wavelength propagating in the hollow-core of the hollow-core optical fiber; and a second cladding positioned between the central longitudinal axis of the hollow-core optical fiber and the inner surface of the substrate, the second cladding surrounding the central longitudinal axis of the hollow-core optical fiber and including a plurality of cladding elements configured to provide an anti-resonant effect at the wavelength , the anti-resonant effect operable to confine the optical signal at the wavelength in the hollow-core.

An optical element may include a plurality of subsurface induced scattering centers formed in the optical element, where the plurality of subsurface induced scattering centers scatter light passing through the optical element. In some implementations, the plurality of subsurface induced scattering centers may form a scattering region in the optical element. Additionally, or alternatively, the plurality of subsurface induced scattering centers may spatially vary transmission of light through the optical element. The optical element may be an optical waveguide, a bulk optic, and/or the like.

The present invention is directed to an optical fiber grating having a core, that is capable of controlling the light signal transmission therethrough by causing at least one of: at least one spectral peak, and/or at least one spectral dip in its core light transmission spectrum, corresponding to at least one predetermined wavelength. The inventive optical fiber diffraction grating comprises at least one longitudinally positioned structural element of a predetermined geometric profile and that is configured for diffracting a portion of the transmitted light signal at at least one predefined wavelength thereof, from at least one core mode into at least one of: at least one cladding mode and/or at least one radiating mode. Various embodiments of a number of novel techniques for fabrication of the inventive optical fiber diffraction grating are provided, inclusive of a novel technique for fabricating the inventive grating from a single material. Advantageously, such novel fabrication techniques rely on configuration of a desired geometric profile for the at least one structural element portion of the novel grating, each profile comprising a number of readily configurable parameters that can be selected and/or adjusted during fabrication, to produce a variety of novel fiber diffraction gratings, each having a corresponding specific desirable core transmission spectrum having at least one of: least one spectral peak, and/or at least one spectral dip therein, corresponding to at least one specific desired wavelength, dependent on the configuration of the applicable geometric profile.

A photonic crystal fiber according to the present invention has a plurality of holes arranged in the optical fiber along a longitudinal direction, in which the holes are arranged such that, in a cross section, a hole ratio which is an area of the holes per unit area is larger in a central side than in an outer side in a portion corresponding to a cladding and that a wide core area can be obtained while the number of modes that can be propagated is limited to several. Moreover, in a high-power optical transmission system according to the present invention, the amount of axis misalignment between the central axis of a laser oscillator and the central axis of the photonic crystal fiber is less than or equal to a certain amount.

A microstructured optical fiber for generating supercontinuum light. The optical fiber includes a core and a cladding region surrounding the core. The optical fiber includes a first fiber length section, a second fiber length section as well as an intermediate fiber length section between said first and second fiber length sections. The first fiber length section has a core with a first characteristic core diameter larger than about 7 ?m. The second fiber length section has a core with a second characteristic core diameter, smaller than said first characteristic core diameter. The intermediate length section of the optical fiber includes a core which is tapered from said first characteristic core diameter to the second characteristic core diameter over a tapered length. Also, a supercontinuum light source including an optical fiber and a pump light source.

A laser-written waveguide comprising, an optical substrate having a first refractive index, a plurality of laser-written tracks buried within the optical substrate and having a second refractive index lower than the first refractive index, one or more concentric geometric regions bounding the plurality of laser-written tracks and a waveguide channel delimited by said concentric geometric regions, wherein said waveguide channel is configured to allow formation of an optical mode.

A tapered waveguide is optically connected to an end surface of an optical fiber bundle part, and has a tapered part that changes in outside diameter in a tapered shape. The fiber bundle part is optically connected to the end surface of the large-diameter side of the waveguide. The entire waveguide has a substantially uniform index of refraction. A delivery fiber is optically connected to the end surface on the small-diameter side of the waveguide. As with the fiber bundle part the delivery fiber passes through a hole in a capillary and is affixed. The capillaries are each affixed to a retaining member such that the fiber bundle part, the waveguide, and the delivery fiber are disposed on the same axis and optically connected. The waveguide is retained in a state floating from the retaining member, and the outside surface of the waveguide is not in contact with the retaining member.

A monolithic optical element for generating broadband radiation upon receiving input radiation at an input end of the optical element is disclosed, the optical element including: a hollow core region for guiding the input radiation along a longitudinal axis of the optical element towards an output end of the optical element; a cladding region surrounding the core region along the longitudinal axis and including transversally arranged micro-structures configured to provide non-linear optical behavior to the optical element causing the generation of the broadband radiation; and a supporting region surrounding the cladding region along the longitudinal axis of at least part of the optical element, wherein the supporting region has a transversal dimension which is sufficiently large to render the at least part of the optical element substantially rigid.

The invention relates to a microstructured optical fiber for generating supercontinuum light upon feeding of pump light. The light can be incoherent light. The microstructured optical fiber has a first section and a second section, where the first and second sections have one or more different features. The invention also relates to a supercontinuum source comprising a microstructured optical fiber according to the invention.