Bismuth (Bi) doped optical fibers (BiDF) and Bi-doped fiber amplifiers (BiDFA) are shown and described. The BiDF comprises a gain band and an auxiliary band. The gain band has a first center wavelength (λ1) and a first six decibel (6 dB) gain bandwidth. The auxiliary band has a second center wavelength (λ2), with λ2>λ1. The system further comprises a signal source and a pump source that are optically coupled to the BiDF. The signal source provides an optical signal at λ1, while the pump source provides pump light at a pump wavelength (λ3).

A single mode optical fiber having a core made from silica and less than or equal to about 11 weight % germania and having a maximum relative refractive index Δ.sub.1MAX. The optical fiber also has an inner cladding surrounding the core and having a minimum relative refractive index Δ.sub.2MIN, a first outer cladding surrounding the inner cladding and a second outer cladding surrounding the first outer cladding. The viscosity at 1650° C. of the second outer cladding minus the viscosity at 1650° C. of the first outer cladding is greater than 0.1e.sup.7 Poise, and Δ.sub.1MAX>Δ.sub.2MIN. The single mode optical fiber may also have an outer cladding surrounding the inner cladding made from silica or SiON. The first outer cladding has a maximum relative refractive index Δ.sub.3MAX, and Δ.sub.3MAX>Δ.sub.2MIN.

An optical fiber having a core comprising silica and greater than 1.5 wt % chlorine and less than 0.5 wt % F, said core having a refractive index Δ.sub.1MAX, and an inner cladding region having refractive index Δ.sub.2MIN surrounding the core, where Δ.sub.1MAX>Δ.sub.2MIN.

Laser waveguides, methods and systems for forming a laser waveguide are provided. The waveguide includes an inner cladding layer surrounding a central axis and a glass core surrounding and located outside of the inner cladding layer. The glass core includes a laser-active material. The waveguide includes an outer cladding layer surrounding and located outside of the glass core. The inner cladding, outer cladding and/or core may surround a hollow central channel or bore and may be annular in shape.

An optical boroaluminate glass article comprises: from greater than or equal to 10.0 mol % to less than or equal to 30.0 mol % Al.sub.2O.sub.3; from greater than or equal to 10.0 mol % to less than or equal to 55.0 mol % CaO; from greater than or equal to 10.0 mol % to less than or equal to 25.0 mol % B.sub.2O.sub.3; from greater than or equal to 0.0 mol % to less than or equal to 30.0 mol % SiO.sub.2; and from greater than or equal to 1.0 mol % to less than or equal to 20.0 mol % refractive index raising components. The optical boroaluminate glass article has a refractive index of the glass article, measured at 589.3 nm, of greater than or equal to 1.62, and a density of less than or equal to 4.00 g/cm.sup.3.

A flame-retardant composition endowed with intumescent properties which consists of an acrylic resin, a dehydrating compound, a blowing agent and, optionally, a fluorocarbon-based polymer.

A flame-retardant composition endowed with intumescent properties which consists of an acrylic resin, a dehydrating compound, a blowing agent and, optionally, a fluorocarbon-based polymer.

A method of manufacturing a quartz glass fibre includes producing a quartz glass primary preform by modified chemical vapor deposition (MCVD) in a quartz glass substrate tube and inserting the quartz glass primary preform into a glass jacketing tube. Defect-generating UV radiation is irridiated into the cross-sectional area of the glass jacketing tube while combining the quartz glass primary preform with the glass jacketing tube in the jacketing process to form a cladding layer to a secondary preform. A quartz glass fibre is pulled from the secondary preform.

A system for drawing optical fiber in microgravity including a sealed housing to prevent infiltration of at least humidity and filled with a dry environment, a preform holder located within the sealed housing to hold preform material, a furnace located within the sealed housing to receive the preform material from the preform holder and to heat the preform material from which the optical fiber is pulled, a feed system to move the preform material from the preform holder to the furnace, a drawing mechanism located within the sealed housing to pull the optical fiber from the preform material within the furnace, a diameter monitor located within the sealed housing to measure a diameter of the optical fiber and a fiber collection mechanism located within the sealed housing to gather and store the optical fiber.

A system for drawing optical fiber in microgravity including a sealed housing to prevent infiltration of at least humidity and filled with a dry environment, a preform holder located within the sealed housing to hold preform material, a furnace located within the sealed housing to receive the preform material from the preform holder and to heat the preform material from which the optical fiber is pulled, a feed system to move the preform material from the preform holder to the furnace, a drawing mechanism located within the sealed housing to pull the optical fiber from the preform material within the furnace, a diameter monitor located within the sealed housing to measure a diameter of the optical fiber and a fiber collection mechanism located within the sealed housing to gather and store the optical fiber.