This application relates generally to an optical fiber for the delivery of infrared light where the polarization state of the light entering the fiber is preserved upon exiting the fiber and the related methods for making thereof. The optical fiber has a wavelength between about 0.9 ?m and 15 ?m, comprises at least one infrared-transmitting glass, and has a polarization-maintaining (PM) transverse cross-sectional structure. The infrared-transmitting, polarization-maintaining (IR-PM) optical fiber has a birefringence greater than 10.sup.?5 and has applications in dual-use technologies including laser power delivery, sensing and imaging.

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 drawing different materials includes forming a first material into a preform body defining at least one channel extending therethrough having a first cross-sectional area. A first element formed of a second material is inserted into the channel and with the preform body creates a preform assembly. The first element has a cross-sectional area that is less than the cross-sectional area of the channel, and the second material has a higher melting temperature than the first material. The preform assembly is heated so that the first material softens and the preform assembly is drawn so that the preform body deforms at a first deformation rate to a smaller cross-sectional area and the first element substantially maintains a constant cross-sectional area throughout the drawing process. Upon completion of the drawing step, the cross-sectional area of the channel is equivalent to the cross-sectional area of the first element.

A high-divergence-angle optical fiber apparatus is disclosed that includes a multimode optical fiber having a distal end and a divergence angle . A light-redirecting structure is operably disposed at the distal end and consists of an array of between 1 and 10 layers of fused glass microspheres. The light-redirecting structure defines a divergence angle , wherein 2. A light source system that utilizes the high-divergence-angle optical fiber apparatus is also disclosed.

A method of drawing different materials includes forming a first material into a preform body defining at least one channel extending therethrough having a first cross-sectional area. A first element formed of a second material is inserted into the channel and with the preform body creates a preform assembly. The first element has a cross-sectional area that is less than the cross-sectional area of the channel, and the second material has a higher melting temperature than the first material. The preform assembly is heated so that the first material softens and the preform assembly is drawn so that the preform body deforms at a first deformation rate to a smaller cross-sectional area and the first element substantially maintains a constant cross-sectional area throughout the drawing process. Upon completion of the drawing step, the cross-sectional area of the channel is equivalent to the cross-sectional area of the first element.

Provided are an apparatus and a method for manufacturing a bent optical fiber. The apparatus and the method make the temperature distribution between irradiated surfaces and rear surfaces of optical fibers and between the optical fiber in the middle and the optical fibers at the both sides uniform when forming a bent portion by using an infrared laser. An apparatus for manufacturing a bent optical fiber formed of an optical fiber having a bent portion includes a bending formation mechanism that holds the optical fiber and forms the bent portion, a fiber feeding mechanism that feeds the optical fiber toward the bending formation mechanism, a light-source mechanism including a light source that emits laser to a portion of the periphery of the optical fiber in which the bent portion is formed, and a rear reflective member disposed to face the light source with the optical fiber interposed therebetween.

The present invention relates to a method (200, 400, 500, 600) for drawing a bare optical fiber (118) from a cylindrical glass preform (102) in a furnace chamber (104) by hanging the cylindrical glass preform (102) near a first end (104a) of the furnace chamber (104), injecting first and second inert gasses inside the furnace chamber (104) in a predefined ratio of 0.3 to 5, and melting the cylindrical glass preform (102) while maintaining a positive pressure in the furnace chamber (104) to form the bare optical fiber (118) such that a Bare Fiber Diameter (BFD) variation of the bare optical fiber (118) is less than 0.1 micrometers (?m) from a mean diameter of the bare optical fiber (118).

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 glass cane is manufactured by filling a glass tube with a combination of glass structures forming a cross-sectional pattern within the glass tube, to form a preform. The preform is attached to a draw assembly, such as a draw tower. The draw assembly is operated o draw the preform to a reduced-diameter glass cane by passing the preform through a furnace of the draw assembly while pulling the preform or the reduced-diameter glass cane and rotating the preform or the reduced-diameter glass cane.

Provided is a method for producing glass fiber, capable of stably performing the spinning of glass fibers without mixing of red crystals in glass fibers. When glass fibers are formed by discharging, from a nozzle tip, a molten glass obtained by melting glass raw materials mixed so as to give a glass composition including, when melted, in relation to the total amount thereof, SiO.sub.2 in a range from 57.0 to 62.0% by mass, Al.sub.2O.sub.3 in a range from 15.0 to 20.0% by mass, MgO in a range from 7.5 to 12.0% by mass, and CaO in a range from 9.0 to 16.5% by mass, and having a total content of SiO.sub.2, Al.sub.2O.sub.3, MgO and CaO of 98.0% by mass or more, the glass composition includes B.sub.2O.sub.3, Li.sub.2O, or B.sub.2O.sub.3 and Li.sub.2O as an additive or additives capable of suppressing the generation of red crystals.