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 method of capturing soot includes the steps: combusting a first precursor in a burner to produce a soot stream, the soot stream comprising soot and exiting the burner at an outlet; and directing a capture medium to the soot stream, the capture medium contacting the soot in an impact region, the soot having a temperature greater than 50 C. in the impact region.

A method of forming an optical element is provided. The method includes producing silica-based soot particles using chemical vapor deposition, the silica-based soot particles having an average particle size of between about 0.05 m and about 0.25 m. The method also includes forming a soot compact from the silica-based soot particles and doping the soot compact with a halogen in a closed system by contacting the silica-based soot compact with a halogen-containing gas in the closed system at a temperature of less than about 1200 C.

A polarization-maintaining optical fiber includes at least one polarization maintaining core, a first cladding surrounding the at least one polarization maintaining core, and a second cladding surrounding the first cladding. The at least one polarization maintaining core includes a core and a pair of low-refractive-index portions each having a refractive index lower than a refractive index of the core. In a cross section, at least a portion of an outer periphery of each of the pair of low-refractive-index portions is in contact with the core, and an outer periphery of the core, excluding portions each being in contact with the low-refractive-index portions, has a circular shape. A maximum value of an absolute value of a residual stress in the cross section is 100 MPa or less. A mode-field flattening f is 0.05 to 0.40 at any wavelength within a range of 850 nm to 1625 nm.

The present disclosure provides a method for fabrication of a glass preform. The method includes production of soot particles in a combustion chamber using a precursor material. The heating of the precursor material produces the soot particles along with one or more impurities. In addition, the method includes agglomeration of the soot particles. Further, the method includes separation of the soot particles from the one or more impurities. Also, the separation of the soot particles is performed in a cyclone separator. Furthermore, the method includes collection of the soot particles. Also, the soot particles are compacted with facilitation of a preform compaction chamber. Also, the compacted preform is sintered with facilitation of a sintering furnace. The compaction of the soot particles followed by sintering results in formation of the glass preform.

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 .sub.1MAX, and an inner cladding region having refractive index .sub.2MIN surrounding the core, where .sub.1MAX>.sub.2MIN.

A method for forming an optical quality glass is provided. The method includes contacting silica soot particles with a hygroscopic additive, forming a silica soot compact, and removing the hygroscopic additive from the silica soot compact. A method of forming a cladding portion of an optical fiber preform is also provided.

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.

A method for manufacturing a multicore optical fiber includes a step of forming ring-shaped closed-end holes to axially extend from a first end toward a second end of a glass rod; a step of heating bottom parts of the ring-shaped closed-end holes and softening center rods surrounded by the ring-shaped closed-end holes; a step of pulling out the center rods toward a side of the first end, forming columnar closed-end holes from the ring-shaped closed-end holes, and treating the glass rod as a cladding material; a connecting step of connecting a supporting pipe to the first end; an inserting step of inserting core rods into the columnar closed-end holes after the connecting step; and a drawing step of drawing the cladding material and the core rods while heating a portion near the second end and integrating the cladding material and the core rods after the inserting step.

Provided is an optical fiber manufacturing method that uses a low-cost large optical fiber preform having high precision. The optical fiber manufacturing method includes at least a positioning step of positioning core rods in a hollow carbon pipe that contains carbon as a main component, a soot preform preparation step of filling a gap between the carbon pipe and the core rods with silica powder that contains SiO.sub.2 as a main component, thereby producing a soot preform, a consolidating step of introducing the soot preform into a furnace and consolidating the silica powder, thereby producing a transparent intermediate preform from the soot preform, an extraction step of extracting the transparent intermediate preform from the carbon pipe, and a drawing step of drawing the transparent intermediate preform, thereby manufacturing an optical fiber.