A manufacturing method of a porous glass base material for optical fiber includes: controlling a flow rate of a raw material liquid of an organic siloxane by a liquid mass flow controller; introducing raw material liquid to a raw material liquid nozzle of a vaporizer by a raw material liquid pipe; ejecting raw material liquid into the vaporizer; mixing raw material liquid and carrier gas to vaporize raw material liquid to form mixed gas; supplying mixed gas to a burner; combusting mixed gas together with a combustible gas and a combustion supporting gas in the burner to produce SiO.sub.2 particles; depositing SiO.sub.2 particles on a starting core base material to form the porous glass base material; and closing an open/close valve on a flow path of the raw material liquid pipe to stop supply of raw material liquid, while continuing to supply carrier gas, combustible gas, and combustion supporting gas.

A manufacturing apparatus of a porous glass base material for optical fiber includes: a liquid mass flow controller for controlling a flow rate of a raw material liquid of an organic siloxane; a vaporizer for mixing the raw material liquid and a carrier gas to vaporize the raw material liquid to form a mixed gas in which a raw material gas and the carrier gas are mixed; a raw material liquid nozzle for ejecting the raw material liquid into the vaporizer; a carrier gas supply pipe for supplying the carrier gas into the vaporizer; a raw material liquid pipe for introducing the raw material liquid into the raw material liquid nozzle; a burner for combusting the mixed gas together with a combustible gas and a combustion supporting gas to produce SiO.sub.2 fine particles; a mixed gas pipe; an open/close valve; and a purge gas supply pipe.

A method for manufacturing an optical fiber preform includes a deposition step and an introduction step. In the deposition step, glass fine particles are generated from a glass raw material gas in a flame obtained by burning a flammable gas supplied to a burner, and the glass fine particles are deposited to produce a hollow porous glass preform. In the introduction step, a first gas is introduced into an inside of a hollow of the porous glass preform, and a second gas is introduced to an outside of the porous glass preform. In the method, at least one of the first gas and the second gas is a gas containing halogen. In the gas introduction step, the gas containing halogen is introduced so that a first partial pressure of the first gas and a second partial pressure of the second gas are different from each other.

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.

The present disclosure relates to a method for forming a glass, ceramic or composite material. The method may involve initially forming a plurality of tubes and then performing a coating operation to coat the plurality of tubes with materials containing metal or metalloid elements, including inorganic compounds, organometallic compounds, or coordination complexes to form coated tubes. The method may further include performing at least one of a thermal operation or a thermochemical operation on the coated tubes to form a solid glass, ceramic, or composite structure with dimensions representing at least one of a rod or fiber.

The present disclosure relates to a method for forming a glass, ceramic or composite material. The method may involve initially forming a plurality of tubes and then performing a coating operation to coat the plurality of tubes with materials containing metal or metalloid elements, including inorganic compounds, organometallic compounds, or coordination complexes to form coated tubes. The method may further include performing at least one of a thermal operation or a thermochemical operation on the coated tubes to form a solid glass, ceramic, or composite structure with dimensions representing at least one of a rod or fiber.

A porous glass base material manufacturing apparatus for an optical fiber includes: a liquid mass flow controller for controlling a flow rate of raw material liquid of an organic siloxane; a vaporizer for mixing raw material liquid and carrier gas to vaporize raw material liquid to form mixed gas; a raw material liquid nozzle for ejecting raw material liquid into the vaporizer; a carrier gas supply pipe for supplying carrier gas into the vaporizer; a raw material liquid pipe for introducing raw material liquid into the nozzle; a burner for combusting mixed gas with combustible gas and combustion supporting gas to produce SiO.sub.2 particles; a mixed gas pipe for supplying mixed gas to the burner; an open/close valve on a flow path of the raw material liquid pipe; and a purge gas supply pipe that joins the raw material liquid pipe between the valve and the raw material liquid nozzle.

A manufacturing apparatus of a porous glass base material for optical fiber includes: a liquid mass flow controller for controlling a flow rate of a raw material liquid of an organic siloxane; a vaporizer for mixing the raw material liquid and a carrier gas to vaporize the raw material liquid to form a mixed gas in which a raw material gas and the carrier gas are mixed; a raw material liquid nozzle for ejecting the raw material liquid into the vaporizer; a carrier gas supply pipe for supplying the carrier gas into the vaporizer; a raw material liquid pipe for introducing the raw material liquid into the raw material liquid nozzle; a burner for combusting the mixed gas together with a combustible gas and a combustion supporting gas to produce SiO.sub.2 fine particles; a mixed gas pipe; an open/close valve; and a purge gas supply pipe.

A fiber sensor includes an optical fiber configured for operation at a wavelength from about 800 nm to about 1600 nm. The optical fiber includes a cladding that is defined by a fiber outer diameter and a core that is surrounded by the cladding. The core of the optical fiber has a Rayleigh scattering coefficient, .sub.s, that is controlled by controlling a concentration of one or more dopants in the core. The Rayleigh scattering coefficient is tuned to be within a predetermined range of an optimum Rayleigh scattering coefficient for a given total length, L, of the optical fiber. The predetermined range is from about 70% of the optimum .sub.s to about 130% of the optimum .sub.s.

A porous glass base material manufacturing apparatus for an optical fiber includes: a liquid mass flow controller for controlling a flow rate of raw material liquid of an organic siloxane; a vaporizer for mixing raw material liquid and carrier gas to vaporize raw material liquid to form mixed gas; a raw material liquid nozzle for ejecting raw material liquid into the vaporizer; a carrier gas supply pipe for supplying carrier gas into the vaporizer; a raw material liquid pipe for introducing raw material liquid into the nozzle; a burner for combusting mixed gas with combustible gas and combustion supporting gas to produce SiO.sub.2 particles; a mixed gas pipe for supplying mixed gas to the burner; an open/close valve on a flow path of the raw material liquid pipe; and a purge gas supply pipe that joins the raw material liquid pipe between the valve and the raw material liquid nozzle.