A torch for fabricating optical fiber preforms may include a body having a surface and two or more slit-shaped orifices oriented parallel or substantially parallel to each other along the surface. The torch body may further include two or more conduits connected to corresponding orifices. The torch may be used by orienting it relative to a preform substrate, and simultaneously emitting two or more gases from corresponding orifices toward the surface of the preform substrate, such that the gases are involved in a reaction to form a soot.

A burner for synthesization to synthesize glass particles that form a porous glass base material is provided, the burner for synthesization including a raw material gas injection portion to inject raw material gas toward a target, a combustion assisting gas injection portion to inject combustion assisting gas in a direction in which the combustion assisting gas is merged with the raw material gas at a first merging point, and a combustible gas injection portion to inject combustible gas in a direction in which the combustible gas is merged with the combustion assisting gas at a second merging point that is positioned closer to the combustion assisting gas injection portion than the first merging point. In the above-described burner for synthesization, the combustion assisting gas injection portion may also include a plurality of injection ports arranged along one straight line.

The invention provides a production method for a glass particulate deposit M which includes a deposition step where a starting rod 111 and a burner 222 for production of glass particles 130 are installed in a reactor 102, a glass source material is introduced into the burner 222, the glass source material is subjected to flame thermal decomposition in the flame formed by the burner 222 to thereby form glass particles 130, and the formed glass particles 130 are deposited on the starting rod 111 to produce a glass particulate deposit M. In the deposition step of the production method, at least two ejecting ports 231 are provided per one burner 222 for ejecting the glass source material from the burner 222, and a flow rate of the glass source material jetting out through one glass source material ejecting port 231 is from 4 m/s to 60 m/s.

A burner for synthesization to synthesize glass particles that form a porous glass base material is provided, the burner for synthesization including a raw material gas injection portion to inject raw material gas toward a target, a combustion assisting gas injection portion to inject combustion assisting gas in a direction in which the combustion assisting gas is merged with the raw material gas at a first merging point, and a combustible gas injection portion to inject combustible gas in a direction in which the combustible gas is merged with the combustion assisting gas at a second merging point that is positioned closer to the combustion assisting gas injection portion than the first merging point. In the above-described burner for synthesization, the combustion assisting gas injection portion may also include a plurality of injection ports arranged along one straight line.

A torch for fabricating optical fiber preforms may include a body having a surface and two or more slit-shaped orifices oriented parallel or substantially parallel to each other along the surface. The torch body may further include two or more conduits connected to corresponding orifices. The torch may be used by orienting it relative to a preform substrate, and simultaneously emitting two or more gases from corresponding orifices toward the surface of the preform substrate, such that the gases are involved in a reaction to form a soot.

Monolithic optical structures include a plurality of layer with each layer having an isolated optical pathway confined within a portion of the layer. The monolithic optical structure can be used as an optical fiber preform. Alternatively or additionally, the monolithic optical structure can include integrated optical circuits within one or more layers of the structure. Monolithic optical structures can be formed by performing multiple passes of a substrate through a flowing particle stream. The deposited particles form an optical material following consolidation. Flexible optical fibers include a plurality of independent light channels extending along the length of the optical fiber. The fibers can be pulled from an appropriate preform.