A method for manufacturing a glass preform, the method having: a depositing step for installing a starting rod and a burner for generating glass fine particles in a reaction container, introducing a siloxane as a glass raw material to the burner, oxidizing the glass raw material in a flame formed by the burner and generating glass fine particles, depositing the generated glass fine particles on the starting rod and fabricating a glass fine particle deposited body; and a transparentizing step for heating the glass fine particle deposited body and manufacturing a transparent glass preform, wherein, after the depositing step, the transparentizing step is performed after the glass fine particle deposited body is heated for a time range of one to eight hours in an oxygen-containing atmosphere at a temperature lower than the temperature of the transparentizing step.

A production method and others according to the present embodiment are provided with a structure for effectively preventing occurrence of accidental spiking during drawing of a preform. In order to control the residual He-concentration in the center part of the preform, a transparent glass rod that has a predetermined outer diameter and is already sintered but is not doped with an alkali metal yet is annealed in in the atmosphere not containing He gas for an annealing time determined by referring to result data in which the relationship between the annealing time and the residual He-concentration is previously recorded for each outer diameter. In the result data, actually measured data of the residual He-concentration in a produced optical fiber preform and the annealing time are accumulated as annealing treatment results.

Preparation of halogen-doped silica is described. The preparation includes doping silica with high halogen concentration and sintering halogen-doped silica to a closed-pore state. The sintering includes a high pressure sintering treatment and a low pressure sintering treatment. The high pressure sintering treatment is conducted in the presence of a high partial pressure of a gas-phase halogen doping precursor and densifies a silica soot body to a partially consolidated state. The low pressure sintering treatment is conducted in the presence of a low partial pressure of gas-phase halogen doping precursor and transforms a partially consolidated silica body to a closed-pore state. The product halogen-doped silica glass exhibits little foaming when heated to form fibers in a draw process or core canes in a redraw process.

The present disclosure provides a method for sintering of an optical fiber preform. The method includes preheating of the optical fiber preform in a sintering chamber. In addition, the method includes first downfeeding of the optical fiber preform into a sintering furnace in the presence of helium gas and chlorine gas. The first downfeeding of the optical fiber preform facilitates sintering of an outer layer of the optical fiber preform. Further, the method includes pulling out the optical fiber preform from the sintering furnace in presence of chlorine gas and at least one of nitrogen gas and helium gas. Further, the method includes second down feeding of the optical fiber preform in the sintering furnace in the presence of nitrogen gas and chlorine gas. The second downfeeding of the optical fiber preform facilitates sintering of the optical fiber preform.

The present disclosure provides a method for sintering of an optical fibre preform. The method includes manufacturing of the optical fibre preform. In addition, the method includes drying and sintering of the optical fibre preform. In addition, drying and sintering of the optical fibre preform results into a sintered optical fibre preform. Further, the method includes preparation of a glass rod from the sintered optical fibre preform. Furthermore, the method includes insertion of the glass rod into a centreline hole of the silica soot preform. The centreline hole is created by removing mandrel from the silica soot preform. Moreover, the method includes drying and sintering of the silica soot preform. Also, drying and sintering of the silica soot results into a sintered silica soot preform. Also, the method includes drawing of a rod from the sintered silica soot preform.

A method of measuring a diameter of a core portion of an optical fiber preform including the core portion having a relatively high refractive index and a clad portion having a relatively low refractive index. The method includes applying parallel light to the optical fiber preform, and measuring the diameter of the core portion from an image captured by receiving the light having transmitted through the optical fiber preform.

According to embodiments, a method of making a micro structured glass article 100 includes bundling M bare optical fibers in a fiber bundle, wherein M is an integer greater than 100. Thereafter, the fiber bundle may be inserted in a cavity of a soot preform. The soot preform may have a density of less than or equal to 1.5 g/cm3 and comprise silica-based glass soot. The soot preform and inserted fiber bundle may then be consolidated to form a microstructured glass article preform. The micro structured glass article preform may then be drawn into the microstructured glass article 100 comprising M core elements 102 embedded in a cladding matrix 104.

Disclosed herein are methods for forming an optical fiber preform using organic silica and germania precursors. The method includes depositing soot composed of germanium dioxide and silica on a substrate, removing the substrate, conducting a dehydration step and one or more heating steps under an oxygen-containing atmosphere to form the preform. Also disclosed are optical fibers drawn from the preforms produced herein.

This invention provides a manufacturing method for an optical fiber. In this invention, when the core layer loose body and the cladding layer loose body are deposited, the oxyhydrogen flame is used make a temperature of an interface between the core layer and the cladding layer rise, such that silicon dioxide at the interface appropriately contracts to form an isolation layer with a relatively high density. In addition, in this invention, a hollow glass tube is used as a target rod, and the hollow glass tube which is the target rod is directly connected with the core layer loose body. During the subsequent dehydration, not only a dehydration atmosphere penetrates from the outside to the inside of the cladding layer loose body, but also the dehydration atmosphere directly enters the core layer through the hollow glass tube.

An improved process for preheating and doping a preform having a consolidated glass core and a silica soot cladding surrounding core involves waveguiding millimeter wavelength electromagnetic radiation into the preform to cause heating of the preform within the interior via absorption of the electromagnetic radiation by silica in the preform while the preform is exposed to a gas phase dopant.