Abstract: A magnetic field sensor in the form of a multi-material optical fiber is described. The magnetic sensing optical fiber of the present disclosure can leverage optics and magnetostriction to sense an external magnetic field adjacent to the fiber. The magnetic sensing optical fiber can be customized to achieve various desired sensing sensitivities for various applications, including measuring while drilling and unconventional oil and gas applications. In one example, an optical fiber can include a cladding that can extend from a first end to a second end of the optical fiber. The optical fiber can further include an optical core within the cladding. The optical core can extend along the optical fiber between the first end and the second end. The optical fiber can also include a magnetostrictive element within the cladding. The magnetostrictive element can extend along the optical fiber between the first end and the second end.

Abstract: An optical fiber includes: a core including a photosensitive material disposed therein, the core having a first index of refraction; a depressed cladding surrounding the core and having a second index of refraction that is lower than the first index of refraction; and an outer cladding surrounding the depressed cladding and having a third index of refraction that is higher than the depressed cladding.

Abstract: An apparatus for estimating a shape, the apparatus including: an optical fiber configured to conform to the shape and having a first core offset from a centerline of the optical fiber, the first core having an optical characteristic configured to change due to a change in shape of the optical fiber wherein a change in the optical characteristic is used to estimate the shape. A method for estimating a shape is also disclosed.

Abstract: An apparatus for determining a property, the apparatus including: an optical fiber having a series of fiber Bragg gratings, each fiber Bragg grating in the series being characterized by a light reflection frequency at which the fiber Bragg grating reflects light; wherein: the light reflection frequency for each fiber Bragg grating is different from the light reflection frequency of each adjacent fiber Bragg grating to minimize resonance of light between at least two of the fiber Bragg gratings in the series; at least two fiber Bragg gratings in the series have light reflection frequencies that overlap; and a change in the light reflection frequency of each fiber Bragg grating in the series is related to the property at the location of the each fiber Bragg grating.

Abstract: A method of manufacturing an optical fiber includes: disposing an axially extending preform structure on a support structure; directing a gas mixture along a major axis of the preform structure in a first axial direction; disposing a heating device proximate to the preform structure; and activating the heating device and moving the heating device along the major axis in a second axial direction to heat the preform structure and deposit at least one layer of material on the preform structure, the second axial direction being opposite to the first axial direction.

Abstract: An optical fiber includes: a core including a photosensitive material disposed therein, the core having a first index of refraction; a depressed cladding surrounding the core and having a second index of refraction that is lower than the first index of refraction; and an outer cladding surrounding the depressed cladding and having a third index of refraction that is higher than the depressed cladding.

Abstract: An apparatus for determining a property, the apparatus including: an optical fiber having a series of fiber Bragg gratings, each fiber Bragg grating in the series being characterized by a light reflection frequency at which the fiber Bragg grating reflects light; wherein: the light reflection frequency for each fiber Bragg grating is different from the light reflection frequency of each adjacent fiber Bragg grating to minimize resonance of light between at least two of the fiber Bragg gratings in the series; at least two fiber Bragg gratings in the series have light reflection frequencies that overlap; and a change in the light reflection frequency of each fiber Bragg grating in the series is related to the property at the location of the each fiber Bragg grating.

Abstract: A multiple-layer fiber-optic sensor is described with dual Bragg gratings in layers of different materials, so that the known temperature and strain response properties of each material may be utilized to simultaneously correct the sensor output for temperature and strain effects.

Abstract: A fiber optic construction is described combining low OH (preferably <1 ppm) materials for use in the core and cladding elements with controlled Do/d ratios to provide extended life expectancy fiber optics for use in high-temperature environments.

Abstract: A multi-core optical fiber sensor is described, which sensor includes an optical fiber having at least two cores, wherein the cores have collocated measurement portions, for example in-fiber interferometers or Bragg grating portions. In an exemplary embodiment, the fiber is provided with collocated measurement portions during fiberization to eliminate drift factors and to provide temperature corrected parameter measurement capabilities.

Abstract: The present invention concerns an optical fiber 10 comprising a substantially pure silica glass core 12, a concentric tin-doped core/cladding interface region 14, and a concentric fluorine-doped depressed cladding layer 16. The tin-doped core/cladding interface region 14 comprises a low concentration gradient of tin dioxide, which advantageously results in a de minimis refractive index change, resistance to hydrogen incursion, and thermal stability of any fiber Bragg gratings written into the interface region 14.

Abstract: An optical fiber resistant to hydrogen-induced attenuation losses at both relatively low and relatively high temperatures includes a substantially pure silica core and a hydrogen retarding layer. The hydrogen retarding coating may be made of carbon, metal, or silicon nitride. The fiber may also include a cladding layer, a second silica layer, and a protective outer sheath.

Abstract: An optical fiber resistant to hydrogen-induced attenuation losses at both relatively low and relatively high temperatures includes a substantially pure silica core and a hydrogen retarding layer. The hydrogen retarding coating may be made of carbon, metal, or silicon nitride. The fiber may also include a cladding layer, a second silica layer, and a protective outer sheath.

Abstract: A preform for a low loss fiber optic cable and method and apparatus for fabricating such a preform is provided. The method includes providing AlCl3 and CVD precursors and locally doping CaCl3. Alkali and/or alkaline earth fluxing agents can be introduced. The alkali and/or alkaline earths are doped along with the aluminum into the silica glass core.

Abstract: There is described a package and method of packaging that provide, in inexpensive form, means for adding accurate amounts of one material to another. The package, which can come as a kit to be added to a lyophilizing bottle and stopper, features a portion that is added to the bottle outlet to confine the material that is to be stored separate from the contents of the bottle. That portion includes a plunger preferably constructed to provide a dual function: that of sealing the stopper against the bottle outlet, and of permanently attaching to the stopper to remove it from the bottle when the plunger is moved within the upper portion. Because of its hollow configuration, the plunger can be used to pour off the resulting mixture.