Abstract: A technique for fabricating a lightguide soot-boule. Gaseous reactants are directed through an inner tube of a torch having a plurality of coaxially aligned tubes. A glassy soot is formed at the output of the torch by a flame hydrolysis reaction and at least a portion of the soot is deposited on a forming soot-boule. The inner tube may be axially moved during the soot deposition process to alter or maintain the refractive index of the boule.

Abstract: An exhaust system (3) for a vapor-phase axial deposition (VAD) system (5) is comprised of the serial combination of an exhaust tube (26), an outlet pipe (27), a soot collection chamber (32) and a discharge line (34). The exhaust tube (26) has a constricted central portion (48) and a flared intake (44) with a gradually turned back end (46).

Abstract: A vapor-phase axial deposition system (5) for fabricating a lightguide soot boule (16). The system (5) is comprised of a short cylindrical housing (10) having end plates (26--26) affixed thereto. A starting member (58) is radially directed into the central portion of the housing (10) and a torch (12) is activated to direct a stream of glassy soot thereat. The member (58) is simultaneously rotated and withdrawn from the housing (10) as a cylindrical, porous, soot boule is formed on the end thereof. The housing (10) having a substantially two-dimensional character eliminates secondary gas flow within the housing (10) resulting in enhanced deposition rates and repeatability.

Abstract: A reactant deposition torch (10) has a plurality of concentric glass tubes (16, 18, 20, 24 and 26). Various gases pass through the tubes (18, 20, 24 and 26) while particle producing reactants pass through the inner tube (16). The concentricity of the tubes is accurately maintained by a plurality of precision machined splines located on the outer periphery of the inner and intermediate tubes (16, 18, 20 and 24). Additionally, the inner tube (16) is movable in the axial direction during the deposition process to controllably alter the amount of reactant to be deposited.