A method of forming an optical fiber preform includes flowing a precursor stream through a burner toward a substrate, the precursor stream comprising a glass precursor gas and a carrier gas, the carrier gas having a kinematic viscosity at 2000 K of greater than 5 cm.sup.2/sec and a ratio of heat capacity to universal gas constant (C.sub.p/R) 2000 K of less than 4; flowing an inflammable gas through the burner; pyrogenically forming glass particles from the glass precursor gas, the pyrogenically forming comprising combusting the inflammable gas; flowing a shield gas through the burner, the shield gas flowing between the precursor stream and the inflammable gas, the shield gas having a kinematic viscosity at 2000 K of greater than 5 cm.sup.2/sec and a ratio of heat capacity to universal gas constant (C.sub.p/R) at 2000 K of less than 4; and depositing the glass particles onto the substrate.

Provided is a glass particulate deposit manufacturing method for manufacturing a glass particulate deposit comprising mounting a fixing jig on an outer periphery of an outermost pipe of a burner; inserting a burner cover from a tip end of the outermost pipe of the burner; and sandwiching and compressing a part of the fixing jig between the burner cover and the outermost pipe of the burner to fix the burner cover to the burner, wherein an outer diameter of a part of the fixing jig that is not compressed is greater than an inner diameter of a part of the burner cover inserted to the tip end of the outermost pipe of the burner.

Provided is a glass particulate deposit manufacturing method for manufacturing a glass particulate deposit comprising mounting a fixing jig on an outer periphery of an outermost pipe of a burner; inserting a burner cover from a tip end of the outermost pipe of the burner; and sandwiching and compressing a part of the fixing jig between the burner cover and the outermost pipe of the burner to fix the burner cover to the burner, wherein an outer diameter of a part of the fixing jig that is not compressed is greater than an inner diameter of a part of the burner cover inserted to the tip end of the outermost pipe of the burner.

A soot deposition burner assembly, having at least one burner including a burner face on a first surface of a burner support. The burner produces a flame which extends generally perpendicularly to the first surface. A burner shield includes a first wall extending generally perpendicularly from the first surface surrounding the burner face. The burner shield has a base end with a first surface area facing toward the first surface and a shield face with a second surface area facing away from the first surface. To reduce the buildup of soot material, the second surface area is smaller than the first surface area, and the wall thickness is less at the shield face than the base end. Additionally, air can be directed along an exterior surface of the first wall from the base end toward the shield face to further reduce soot buildup.