The invention concerns a Photonic Crystal Fiber (PCF) a method of its production and a supercontinuum light source comprising such PCF. The PCF has a longitudinal axis and comprises a core extending along the length of said longitudinal axis and a cladding region surrounding the core. At least the cladding region comprises a plurality of microstructures in the form of inclusions extending along the longitudinal axis of the PCF in at least a microstructured length section. In at least a degradation resistant length section of the microstructured length section the PCF comprises hydrogen and/or deuterium. In at least the degradation resistant length section the PCF further comprises a main coating surrounding the cladding region, which main coating is hermetic for the hydrogen and/or deuterium at a temperature below Th, wherein Th is at least about 50° C., preferably 50° C.<Th<250° C.

A method for the production of synthetic quartz glass using a special cleaning device is provided. The method includes (a) evaporating a production material containing a polymerizable polyalkylsiloxane compound while forming a production material vapor, (b) passing the production material vapor resulting from step (a) through a cleaning device to purify the production material vapor, (c) supplying the purified production material vapor resulting from step (b) to a reaction zone in which the purified production material vapor is converted to SiO.sub.2 particles through oxidation and/or through hydrolysis, (d) depositing the SiO.sub.2 particles resulting from step (c) on a deposition surface, and optionally drying and vitrifying the deposited SiO.sub.2 particles resulting from step (d) to form synthetic quartz glass. The cleaning device includes a bulk of porous silica particles which have a BET specific surface area of at least 2 m.sup.2/g. A device for carrying out the method is also provided.

A method for producing a pore-containing opaque quartz glass includes: (a) producing porous SiO.sub.2 granulate particles from synthetically produced SiO.sub.2, (b) thermally densifying the SiO.sub.2 granulate particles to form partly densified SiO.sub.2 granulate particles, (c) forming a dispersion from the partly densified SiO.sub.2 granulate particles, (d) comminuting the partly densified SiO.sub.2 granulate particles to form a slip containing comminuted SiO.sub.2 granulate particles, (e) shaping the slip into a shaped body and forming a porous SiO.sub.2 green body with a green density rG, and (f) sintering the SiO.sub.2 green body into opaque quartz glass. To produce opaque quartz glass that is also suited for the use of spray granulate, during step (b), partly densified SiO.sub.2 granulate particles are produced with a specific surface BET-(A) between 0.025 and 2.5 m.sup.2/g, and during step (d), comminuted SiO.sub.2 granulate particles are produced with a specific surface BET-(B) between 4 and 10 m.sup.2/g.

An optical fiber includes a core and a cladding surrounding an outer periphery of the core and has a refractive index profile in which a relative refractive index difference with respect to a distance r from a center of the core is represented by Δ(r), where a value of A represented by

A=−∫.sub.0.sup.0.22MFD.sup.1.31(Δ(r)−Δ.sub.ref(r))dr+∫.sub.0.22MFD.sub.1.31.sup.0.44MFD.sup.1.31(Δ(r)−Δ.sub.ref(r))dr  (Formula 1)

is 0.3%.Math.μm or less, where a unit of r is μm, a unit of a relative refractive index difference Δ(r) is %, Δ.sub.ref(r)=−0.064r+0.494, and MFD.sub.1.31 is a mode field diameter at a wavelength of 1.31 μm.

According to some embodiments a method of processing an optical fiber comprises the steps of: (i) drawing the fiber at a drawing rate of at least 30 m/sec; and (ii) cooling the drawn fiber in a gas at an average cooling rate less than 5000° C./s, such that said cooling reduces the temperature of the fiber from an entering temperature in the range between 1500° C. and 1700° C. to another temperature in the range between 1200° C. and 1400° C., the gas being at a temperature between 800° C. and 1500° C.; and the thermal conductivity κ of the gas being not greater than 1.5×10.sup.−4 cal/cm-s-K for at least one temperature within a range of 800° C. to 1500° C. at one atm (atmosphere) pressure absolute.

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.

An optical fiber preform includes: a core formed of silica glass which does not contain Ge, wherein the core has at least one of characteristics in spectrometry of (1) an absorption peak is present at a wavelength of 240 nm to 255 nm, and (2) a wavelength at which an ultraviolet transmittance is 50% or lower is longer than 170 nm.

An optical fiber includes a core, and a clad surrounding an outer circumference of the core, in which a first relative refractive index difference Δ1a is greater than 0, a second relative refractive index difference Δ1b is greater than 0, the first relative refractive index difference Δ1a is greater than the second relative refractive index difference Δ1b, the first relative refractive index difference Δ1a and the second relative refractive index difference Δ1b satisfy a relationship denoted by the following expression: 0.20≦(Δ1a−Δ1b)/Δ1a≦0.88, and a refractive index profile Δ of the core in an entire region of a section of 0≦r≦r1 as a function Δ(r) of a distance r from a center of the core in the radial direction is denoted by the following expression: Δ(r)=Δ1a−(Δ1a−Δ1b)r/r1.

Known methods of producing a three-dimensional glass object comprise the step of shaping of a glass fiber, wherein the glass fiber provided with a protective sheath is fed continuously to a heating source, the protective sheath is removed under the influence of heat, and the glass fiber is softened. In order to facilitate the production of filigree or optically distortion-free and transparent glass objects as much as possible, and also enable the adjustment of optical and mechanical properties with high spatial resolution, in one aspect the glass fiber has a protective sheath with a layer thickness in the range of 10 nm to 10 μm.

Described is a process for the production of synthetic fused silica in which the deposition surface is located for a period of at least 50% of the build-up time of the soot body at a burner distance in which the horizontally integrated luminous intensity of the flame of the burner used in the targetless state is still at least ⅔ of the maximum horizontally integrated luminous intensity of the flame.