The present invention provides a device for measuring the absolute value of the refractive index of a liquid by immersion uses the optical properties of a cylindrical waveguide with a solid core and normal angle of incidence of the light source.

A process of in-situ detection of hollow fiber formation includes immersing a plurality of individual glass fibers in an index-matching material. The index-matching material has a first refractive index that substantially matches a second refractive index of the glass fibers. The process also includes exposing the individual glass fibers to a light source during immersion in the index-matching material. The process further includes utilizing one or more optical components to collect optical data for the individual glass fibers during immersion in the index-matching material. The process also includes determining, based on the optical data, that a particular glass fiber of the plurality of individual glass fibers includes a hollow fiber.

Fibre linear cavity ring down device for decay time-based attenuation sensing, comprising a bi-directional fibre optic coupler having two fibre port coupling sides, a left-hand port side and a right-hand port side, and a port mirror; wherein signal input on one of said sides is coupled to signal output on the other of said sides; wherein the left-hand port side comprises a first fibre port (port 1) for coupling to an optical light source, the left-hand port side comprises a second fibre port (port 2) coupled to said port mirror (mirror 2), and the right-hand port side comprises a third fibre port (port 3) for coupling to a sensor fibre comprising one or more sensors and optically terminated by a sensor fibre mirror (mirror 1). The optical light source may be also an optical light receiver. The optical light source and receiver may preferably be an optical time domain reflectometer.

The present invention provides a device for measuring the absolute value of the refractive index of a liquid by immersion uses the optical properties of a cylindrical waveguide with a solid core and normal angle of incidence of the light source.

One aspect relates to a process for the preparation of a quartz glass body including: i.) providing a silicon dioxide granulate, ii.) making a first glass melt out of the silicon dioxide granulate, iii.) making a glass product out of at least one part of the glass melt, iv.) reducing the size of the glass product to obtain a quartz glass grain, v.) making a further glass melt from the quartz glass grain and vi.) making a quartz glass body out of at least one part of the further glass melt. Furthermore, one aspect relates to a quartz glass body obtainable by this process. Furthermore, one aspect relates to a reactor, which is obtainable by further processing of the quartz glass body.

A monitoring probe is for monitoring a fluid inside a process system. The probe has a first portion comprising a plurality of optical sensors provided along a waveguide for monitoring a plurality of measurands from the fluid, wherein each optical sensor is configured to monitor at least one measurand from the fluid. The first portion of the probe is elongate and is configured to be inserted through an aperture of the process system into a chamber of the process system such that the optical sensors are in communication with the fluid. The probe further has an attachment element for securing the probe to the process system.

Systems and methods are described, and one method includes passing an optical beam through a volume of the gas to a reception surface, applying spectroanalysis to the optical beam received at the reception surface, and determining from the spectroanalysis whether a liquid is carried by the volume of the gas.

A process of in-situ detection of hollow fiber formation includes immersing a plurality of individual glass fibers in an index-matching material. The index-matching material has a first refractive index that substantially matches a second refractive index of the glass fibers. The process also includes exposing the individual glass fibers to a light source during immersion in the index-matching material. The process further includes utilizing one or more optical components to collect optical data for the individual glass fibers during immersion in the index-matching material. The process also includes determining, based on the optical data, that a particular glass fiber of the plurality of individual glass fibers includes a hollow fiber.

A method for determining the refractive index profile of a preform is provided. The method involves: preparing the measured deflection angle distribution, including an extreme value determination of the deflection angle distribution, to obtain a prepared deflection angle distribution; transforming the prepared deflection angle distribution into a prepared refractive-index profile; evaluating the prepared refractive-index profile for the fixation of orientation values for the layer radius and for the layer refractive index of a hypothetical refractive index profile; generating a simulated deflection angle distribution on the basis of the hypothetical refractive-index profile with the orientation values, and transforming the deflection angle distribution into a simulated refractive-index profile; fitting the simulated refractive index profile to the prepared refractive-index profile by iterative adaptation of parameters to obtain a fitted, simulated refractive-index profile which is defined by adapted parameters, and obtaining the refractive index profile as the hypothetical refractive-index profile with the adapted parameters.

A quartz glass body and a process for the preparation of a quartz glass body is disclosed. One process includes providing a silicon dioxide granulate from a pyrogenic silicon dioxide powder, making a glass melt out of the silicon dioxide granulate and making a quartz glass body out of at least part of the glass melt. In at least one process a silicon component different from silicon dioxide is added. A quartz glass body is obtainable by this process. A light guide, an illuminant and a formed body, are each obtainable by further processing of the quartz glass body.