There is provided a sensor fiber including an electrically insulating material having a fiber length. At least one transduction element is disposed along at least a portion of the fiber length and is arranged for exposure to an intake species. A photoconducting element is in optical communication with the transduction element. At least one pair of electrically conducting electrodes are in electrical connection with the photoconducting element. The pair of electrodes extend the fiber length.

There is provided a method to fabricate optical taps and waveguide devices in photonic crystal fibers and other fibers with hollow structures. The method involves a preparation step, where the hollow holes inside the fiber are collapsed or partially modified locally; and a waveguide fabrication step, where a femtosecond laser is focused inside the fiber and used to produce optical waveguides that interact in the region that was previously modified in the preparation step.

The present invention, as disclosed and described herein, in one aspect thereof comprises a preform for making a vortex optical fiber includes a glass cylinder formed substantially of silicone dioxide that defines a core portion along a longitudinal axis of the glass cylinder and a cladding portion surrounding the core portion. The glass cylinder further defines a plurality of holes running parallel to the longitudinal axis from a first end of the glass cylinder to a second end of the glass cylinder.

An object of the present invention is to provide a structure of an optical fiber capable of satisfying desired requirements of an output power, a propagation distance, and a beam quality. In the design of the PCF of the present invention, the PCF has air holes having diameters d and intervals in an overlapping region where a region of A.sub.eff of a desired value or more and a cutoff region in a desired higher-order mode overlap each other on a graph where the horizontal axis represents d/ and the vertical axis represents , so that it is possible to sufficiently cut off the mode which is the desired higher-order mode or more, and thus, it is possible to select a region where the A.sub.eff is large.

Air core optical fiber structures in which the cladding is composed of an engineered optical metamaterial having a refractive index less than unity for at least one specific wavelength band and provides for total internal reflection of optical energy between the air core and metamaterial cladding. According to certain examples, a method of guiding optical energy includes constructing a hollow core optical fiber with an all-dielectric optical metamaterial cladding, coupling optical energy into the optical fiber having an operating wavelength near a resonance of the metamaterial cladding, and guiding the optical energy within the hollow core optical fiber by total internal reflection.

The present invention provides a cylindrical light diffusing device comprising a non-circular core fiber having (i) a fiber core that provides a top hat core irradiance distribution; (ii) light blocking means that prevent frontal light emisson from distal end of the non-circular core fiber; and (iii) a light diffusing section having a diffusing proximal end, a diffusing distal end, and internal scattering features distributed within the fiber core of the light diffusing section along central axis of the fiber core, wherein the light diffusion section emits irradiance in a radially symmetric longitudinally top hat diffusing irradiance distribution.

A method of drawing a material into sheet form includes forming a preform comprising at least one material as a large aspect ratio block wherein a first transverse dimension of the preform is much greater than a second transverse dimension substantially perpendicular to the first transverse dimension. A furnace having substantially linearly opposed heating elements one spaced from the other is provided and the heating elements are energized to apply heat to the preform to create a negative thermal gradient from an exterior surface along the first transverse dimension of the preform inward toward a central plane of the preform. The preform is drawn in such a manner that the material substantially maintains its first transverse dimension and deforms across its second transverse dimension.

A method of producing a microstructured optical fiber is disclosed. The method includes providing a preform and drawing the preform. The preform has a center axis, a length and a first end and a second end and has at least one longitudinal hole extending lengthwise. The method includes inserting a first end of a pressure tube into the hole of the preform at the first end of the preform and subjecting the hole of the preform to a controlled pressure via the pressure tube during the drawing.

A fiber optic drop cable may include a buffer tube having a diameter between approximately 2.20 mm and approximately 3.20 mm to facilitate housing of at least twelve optical fibers. First and second strength rod may be respectively positioned on opposite sides of the buffer tube, and each strength rod may have a diameter between approximately 1.25 mm and approximately 2.10 mm. Additionally, a jacket may be formed around the buffer tube and the strength rods. The jacket may have an elongated cross-sectional shape with a major dimension between approximately 8.0 mm and approximately 9.5 mm and a minor dimension between approximately 4.0 mm and approximately 4.4 mm.

A preform for making a vortex optical fiber comprises a glass cylinder formed substantially of silicone dioxide that defines a core portion along a longitudinal axis of the glass cylinder and a cladding portion surrounding the core portion. The glass cylinder further defines a plurality of holes running parallel to the longitudinal axis from a first end of the glass cylinder to a second end of the glass cylinder.