The present invention discloses a fabrication method and use of a ?40 mm large-size and high-contrast fiber optic image inverter, belonging to the field of manufacturing of fiber optic imaging elements. The light-absorbing glass for preparing the ?40 mm large-size and high-contrast fiber optic image inverter consists of the following components in molar percentage: SiO.sub.2 60-69.9, Al.sub.2O.sub.3 1.0-10.0, B.sub.2O.sub.3 10.1-15.0, Na.sub.2O 1.0-8.0, K.sub.2O 3.0-10.0, MgO 0.1-1.0, CaO 0.5-5.0, ZnO 0-0.1, TiO.sub.2 0-0.1, ZrO.sub.2 0.1-1.0, Fe.sub.2O.sub.3 3.0-6.5, Co.sub.2O.sub.3 0.1-0.5, V.sub.2O.sub.5 0.51-1.5 and MoO.sub.3 0.1-1.0. The fiber optic image inverter has the advantages of low crosstalk of stray light, high resolution and high contrast.

The present application provides a process of fabrication of erbium and ytterbium-co-doped multielements silica glass based cladding-pumped fiber for use as a highly efficient high power optical amplifier.

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 drawn glass element for producing glass optical waveguides is provided. The element has two first length portions with a first cross-sectional area and which define the two ends of the glass element; a second, intermediate length portion between the two first length portions, which has a second cross-sectional area smaller than the first cross-sectional area; a first transition portion between the intermediate length portion and one of the first length portions; and a second transition portion between the intermediate length portion and another of the first length portions. The first and second transition portions have a cross-sectional area that steadily changes and merges from the first cross-sectional area into the second cross-sectional area.

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.

Optical fiber (1) made of a photosensitive glass and with a rectangular cross section, wherein the radius of curvature of a corner of the rectangular cross section is smaller than 100 microns.

A quartz glass tube as a semi-finished product for an optical component that has an inner bore extending along a tube center axis for the acceptance of a core rod and a tube wall limited by an inner casing surface and an outer casing surface is already known; within said tube wall an inner region made of a first quartz glass and an outer region made of a second quartz glass with a different index of refraction surrounding the inner region contact one another at a contact surface which runs around the center axis. In order to provide a quartz glass on this basis that facilitates the production of optical components for special applications such as laser-activated optical components in wand or fiber form, the invention states that the contact surface has a non-round course in the radial cross-section and the inner casing surface has a circular course.

Optical fiber (1) made of a photosensitive glass and with a rectangular cross section, wherein the radius of curvature of a corner of the rectangular cross section is smaller than 100 microns.

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.