An illumination system generating light having at least one wavelength within 200 nm a plurality of nano-sized structures (e.g., voids). The optical fiber coupled to the light source. The light diffusing optical fiber has a core and a cladding. The plurality of nano-sized structures is situated either within said core or at a core-cladding boundary. The optical fiber also includes an outer surface. The optical fiber is configured to scatter guided light via the nano-sized structures away from the core and through the outer surface, to form a light-source fiber portion having a length that emits substantially uniform radiation over its length, said fiber having a scattering-induced attenuation greater than 50 dB/km for the wavelength(s) within 200 nm to 2000 nm range.

A disclosed multimode optical fiber comprises a core and a cladding surrounding the core. The core has an outer radius r.sub.1 in between 20 μm and 30 μm. The cladding includes a first outer cladding region having an outer radius r.sub.4a and a second outer cladding region having an outer radius r.sub.4b less than or equal to 45 μm. The second outer cladding region comprises silica-based glass doped with titania. The optical fiber further includes a primary coating with an outer radius r.sub.5 less than or equal to 80 μm, and a thickness (r.sub.5−r.sub.4) less than or equal to 30 μm. The optical fiber further includes a secondary coating with an outer radius r.sub.6 less than or equal to 100 μm. The secondary coating has a thickness (r.sub.6−r.sub.5) less than or equal to 30 μm, and a normalized puncture load greater than 3.6×10.sup.−3 g/micron.sup.2.

Novel chemical sensors that improve detection and quantification of CO.sub.2 are critical to ensuring safe and cost-effective monitoring of carbon storage sites. Fiber optic (FO) based chemical sensor systems are promising field-deployable systems for real-time monitoring of CO.sub.2 in geological formations for long-range distributed sensing. In this work, a mixed-matrix composite integrated FO sensor system was developed that reliably operates as a detector for gas-phase and dissolved CO.sub.2. A mixed-matrix composite sensor coating on the FO sensor comprising plasmonic nanocrystals and zeolite embedded in a polymer matrix. The mixed-matrix composite FO sensor showed excellent reversibility/stability in a high humidity environment and sensitivity to gas-phase CO.sub.2 over a large concentration range. The sensor exhibited the ability to sense CO.sub.2 in the presence of other geologically relevant gases, which is of importance for applications in geological formations. A prototype FO sensor configuration which possesses a robust sensing capability for monitoring dissolved CO.sub.2 in natural water was demonstrated. Reproducibility was confirmed over many cycles, both in a laboratory setting and in the field.

A co-doped optical fiber is provided having an attenuation of less than about 0.17 dB/km at a wavelength of 1550 nm. The fiber includes a core region in the fiber having a graded refractive index profile with an alpha of greater than 5. The fiber also includes a first cladding region in the fiber that surrounds the core region. Further, the core region has a relative refractive index of about −0.10% to about +0.05% compared to pure silica. In addition, the core region includes silica that is co-doped with chlorine at about 1.2% or greater by weight and fluorine between about 0.1% and about 1% by weight.

Provided is an optical fiber glass preform in which a starting rod and a dummy glass are hardly separated from each other, and a method for manufacturing the glass preform. In the optical fiber glass preform, the dummy glass is fitted into one end of the starting rod, and a part of the dummy glass and the starting rod are surrounded by a clad glass. In the manufacturing method, at the time of connecting the starting rod and the dummy glass, a shape is adjusted in such a manner that an iron is brought into contact with a connection portion and is moved from a starting rod side toward a dummy glass side with appliance of a load.

A fiber optic imaging element includes medium-expansion and a fabrication method including: (1) matching a core glass rod with a cladding glass tube to perform mono fiber drawing; (2) arranging the mono fibers into a mono fiber bundle rod, and then drawing the mono fiber bundle rod into a multi fiber; (3) arranging the multi fiber into a multi fiber bundle rod, and then drawing the multi fiber bundle rod into a multi-multi fiber; (4) cutting the multi-multi fiber, and then arranging the multi-multi fiber into a fiber assembly buddle, then putting the fiber assembly buddle into a mold of heat press fusion process, and performing the heat press fusion process to prepare a block of the fiber optic imaging element with medium-expansion; and (5) edged rounding, cutting and slicing,

The multicomponent oxide glass has a composition including: 45-53 mol % SiO.sub.2; 22-30 mol % B.sub.2O.sub.3; 5-9 mol % Al.sub.2O.sub.3; 0.02-0.10 mol % Sb.sub.2O.sub.3; 0-18 mol % Li.sub.2O; 0-18 mol % Na.sub.2O; 0-18 mol % K.sub.2O; 0-13 mol % MgO; 0-13 mol % CaO; 0-13 mol % BaO; and 0-13 mol % ZnO. When the total content of Li.sub.2O, Na.sub.2O, and K.sub.2O is X mol % and the total content of MgO, CaO, BaO, and ZnO is Y mol %, 11≤X≤18 and 14≤X+Y≤24 hold, and the value of βOH calculated from βOH=α/t, where α represents a height of an absorption peak due to OH groups, observed in a range of 3400 cm.sup.−1 to 3800 cm.sup.−1 of an infrared absorption spectrum in no unit and t represents a thickness of the glass in cm, is 4 cm.sup.−1 or more.

A system, device, and method for laser cooling rare earth doped silica glass using anti-Stokes fluorescence is disclosed. The system includes a rare earth doped and codoped with one or more codopants silica glass; a laser that provides radiation to a first surface and through a body of the rare earth doped silica glass, wherein the laser is tuned from a first wavelength to a second wavelength; and a thermally sensitive device that captures images of the rare earth doped silica glass as the laser is tuned and determines a third wavelength between the first wavelength and the second wavelength where the rare earth doped silica glass is maximumly or near maximumly cooled.

An optical fiber can include a core comprising silica co-doped with nitrogen and chlorine and an outer cladding surrounding the core. In some aspects, the core can be characterized by an annealing temperature of less than or equal to about 1150° C. and/or the core can include a relative refractive index Δ.sub.core in a range of from about 0.15% to about 0.45%.

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.