An optical fiber that is a photonic crystal fiber in which a plurality of holes is arranged along a longitudinal direction of the optical fiber, having a predetermined bending radius R determined according to a transmission distance L of the optical fiber and optical power output from the optical fiber, and having an inter-hole distance and a ratio d/ between a hole diameter d and the inter-hole distance such that light of a predetermined number of modes is transmitted and a bending loss of the light of a fundamental mode with the predetermined bending radius R is equal to or smaller than a predetermined value.

A method of making a microstructured optical fiber including loading the core and cladding materials of the fiber with hydrogen and deuterium at a loading temperature; annealing the fiber at a selected temperature T.sub.anneal; pumping the fiber with radiation; and reducing the temperature of the fiber and storing the fiber at the reduced temperature before the step of pumping the fiber; and wherein the method allows the hydrogen and the deuterium to become bound to the core material and the cladding material.

An economic and reliable fiber hermetic sealing for small devices includes partially stripped optical fibers optically aligned, fixed at one end aligned with an optical source, and a cylindrical solder glass with one or multiple through holes which diameters are greater than those of the stripped fibers. A glass solder preform is contained in a ferrule structure which diameter is bigger than that of said solder glass outer diameter. The ferrule wall around the solder glass is lower than said solder glass height. The solder glass preform sits on a stepped hole with 25-75 degrees chamfered. The glass solder melts at high temperatures and flow into small hole section where the fiber is hermetically sealed and retained. An epoxy with a good adhesion to fiber coating and fiber glass is filled in the cavity blocked by molten solder glass. A glass tubing with an outer diameter greater than that of glass solder and an inner diameter greater than that of coated optical fiber is placed on top of melted solder glass and through both stripped and unstripped fiber sections. In addition, a compliant epoxy is applied on the top of glass tubing where optical fibers exit. A method of making this in accordance with the present system is also described.

A method of making a microstructured optical fiber including loading the core and cladding materials of the fiber with hydrogen and deuterium at a loading temperature; annealing the fiber at a selected temperature T.sub.anneal; pumping the fiber with radiation; and reducing the temperature of the fiber and storing the fiber at the reduced temperature before the step of pumping the fiber; and wherein the method allows the hydrogen and the deuterium to become bound to the core material and the cladding material.

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.

Disclosed are a structure with a substrate-embedded waveguide and a method of forming the structure. The waveguide includes cladding material lining a trench in a substrate, a core in the trench on the cladding material, and at least one cavity within the core. Each cavity extends from one end of the core toward the opposite end and contains a low refractive index material or is under vacuum so the waveguide is an arrow waveguide. An insulator layer is on the substrate and extends laterally over the waveguide and a semiconductor layer is on the insulator layer. Additionally, depending upon the embodiment, an additional waveguide can be aligned above the substrate-embedded waveguide either on the isolation region or on a waveguide extender that extends at least partially through the isolation region and the insulator layer to the waveguide.

Disclosed is an optical fiber probe for an optical treatment including a core, to which incident light is guided, a cladding disposed to surround the core, a side surface divergence part connected to the core and configured to diverge the incident light guided to the core to a side surface of a cylindrical column, a diffusion layer disposed to surround the side surface divergence part, a distal end divergence part connected to the side surface divergence part, having a cylindrical shape, and configured to diverge the incident light guided to the side surface divergence part to the outside, and a coating layer disposed to surround the cladding and the diffusion layer and configured to seal the cladding and the diffusion layer, wherein the refractive index of the cladding is lower than the refractive index of the core, the refractive index of the diffusion layer is higher than the refractive index of the core, and the refractive index of the coating layer is higher than the refractive indices of the cladding and the diffusion layer.

Embodiments of optical fiber may include cladding features that include a material (e.g., fluorine-doped silica glass) that may produce a very low relative refractive index difference with respect to cladding material in which the cladding features are disposed. This relative refractive index difference may be characterized by (n.sub.1n.sub.2)/n.sub.1, where n.sub.1 is the index of refraction of the cladding material in which the cladding features are included, and n.sub.2 is the index of refraction of the cladding features. In certain embodiments, the relative refractive index difference may be less than about 4.510.sup.3. In various embodiments, the configuration of the cladding features including, for example, the size and spacing of the cladding features, can be selected to provide for confinement of the fundamental mode yet leakage for the second mode and higher modes, which may provide mode filtering, single mode propagation, and/or low bend loss.

A uniform temperature profile is provided across the width of the core of a ribbon fiber laser or amplifier by the use of insulating elements at the core edges and a spatially variable gain in the fiber core. High average power ribbon fibers, enable a variety of applications such as practical laser cutting and beam combining.

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.