The invention relates to a method and a device for producing a preform for glass fiber production. The method comprises the steps of providing a carrier gas with a desired, precisely adjusted temperature, loading the carrier gas with halide vapor, mixing the loaded carrier gas with additional gases, and producing the preform in a reaction chamber with substrate.

A supercontinuum source, comprises a pump source and a supercontinuum generator configured for receiving electromagnetic radiation derived from the pump source and for generating supercontinuum radiation, the supercontinuum generator comprising a nonlinear microstructured optical fibre having a core region comprising silica. The core region includes a dopant selected to reduce light-induced non-bridging oxygen hole centre loss in the nonlinear microstructured optical fibre.

An apparatus for optical fiber manufacturing process is provided, including a raw material providing structure, a dopant providing structure, and a preform forming substrate tube. The dopant providing structure is disposed at a downstream side of the raw material providing structure and in communication with the raw material providing structure. The dopant providing structure includes an outer tube, a first inner tube, a first dopant providing container, a second inner tube, and a second dopant providing container. The first inner tube is disposed in the outer tube. The first dopant providing container is disposed in the first inner tube. The second inner tube is disposed in the outer tube at a downstream of the first inner tube. The second dopant providing container is disposed in the second inner tube. The preform forming substrate tube is disposed at a downstream side of the dopant providing structure.

A radiation-resistant laser optical fiber preform core rod at least includes one type of activated ion (Yb.sup.3+, Er.sup.3+) and one or more types of co-doped ion (Al.sup.3+, P.sup.5+, Ge.sup.4+, Ce.sup.3+, F.sup.−), and —OD group of 16-118 ppm. Irradiation resistance of core rod glass can be effectively improved by sequentially performing pre-treatments, i.e. deuterium loading, pre-irradiation and thermal annealing on a preform core rod. Electron paramagnetic resonance test shows that, under the same radiation condition, the radiation induced color center concentration in a preform core rod treated by the method above is lower than in an untreated core rod by one or more orders of magnitude. The obtained core rod can be used for preparing a radiation-resistant rare earth-doped silica fiber, and has the advantages of high laser slope efficiency, low background loss, being able to be used stably in a vacuum environment for a long time, for example.

An apparatus for optical fiber manufacturing process is provided, including a raw material providing structure, a dopant providing structure, and a preform forming substrate tube. The dopant providing structure is disposed at a downstream side of the raw material providing structure and in communication with the raw material providing structure. The dopant providing structure includes an outer tube, a first inner tube, a first dopant providing container, a second inner tube, and a second dopant providing container. The first inner tube is disposed in the outer tube. The first dopant providing container is disposed in the first inner tube. The second inner tube is disposed in the outer tube at a downstream of the first inner tube. The second dopant providing container is disposed in the second inner tube. The preform forming substrate tube is disposed at a downstream side of the dopant providing structure.

The present invention relates to a method of forming an optical fiber precursor including: forming an alkali metal doped tube; inserting an optical fiber core rod within the alkali metal doped tube; forming a cladding jacket around the alkali metal doped tube; and diffusing an alkali metal from the alkali metal doped tube through a surface of the optical fiber core rod. The present invention further relates to an optical fiber preform having: an optical fiber core rod; an alkali metal doped tube surrounding the optical fiber core rod; and a cladding jacket surrounding the alkali metal doped tube.

A method of producing bi-modal particles includes the steps of igniting a first precursor gas using a primary burner thereby producing a first plurality of particles of a first size, fluidly transporting the first plurality of particles down a particle tube, igniting a second precursor gas using a secondary burner thereby producing a second plurality of particles of a second size, flowing the second plurality of particles into the first plurality of particles, and capturing the first and second plurality of particles.

A manufacturing method for an optical fiber, includes: drawing, while heating in a heating furnace, a lower end of an optical fiber preform that is to be an optical fiber having a core consisting of silica glass containing a rare earth element compound. The heating furnace has a temperature profile in which a temperature of the heating furnace increases to a maximum temperature T.sub.max and then decreases from an upstream side of the heating furnace toward a downstream side of the heating furnace. The temperature profile has a changing point at which the temperature decreases more steeply on the downstream side from a position where the maximum temperature T.sub.max is reached. At the maximum temperature, a temperature of the silica glass is higher than or equal to a glass transition temperature and the silica glass is in a single phase.

A method is provided that includes: forming a low-index trench region with a first density; forming an inner barrier layer comprising silica around the trench region at a second density greater than the first density; depositing silica-based soot around the first barrier layer to form an overclad region at a third density less than the second density; inserting a core cane into a trench-overclad structure; forming an outer barrier layer comprising silica in an outer portion of the overclad region at a fourth density greater than the third density; flowing a down dopant-containing gas through the trench-overclad structure to dope the trench region with the down dopant, and wherein the barrier layers mitigate diffusion of the down-dopant into the overclad region; and consolidating the trench-overclad and the core cane.

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.