Abstract: Vapor Axial Deposition (VAD) apparatus and method is provided. The VAD apparatus includes a first torch, a second torch, a thermometer, a controller, and a moving device. The first torch grows a core by depositing a soot at an end of a soot preform arranged on an axis. The second torch grows a clad by depositing a soot on the face of the core. The thermometer detects the temperature of the end of the soot preform along the axis and the temperature of an other/lower portion of the core. The controller calculates a difference between a temperature (T1) of the end of the soot preform and a temperature (T4) of a lower portion of the core and controls the movement of the soot preform according to the difference. The moving device moves the soot preform along the axis according to the instruction of the controller.

Abstract: An apparatus for fabricating a soot preform includes at least one torch for depositing soot generated by flame hydrolysis on the soot preform. A vaporizer vaporizes a liquid source material. A heater heats a dilution gas. The vaporizer and the heater respectively supply, to the torch, the vaporized source material and the heated dilution gas together through a single pipe.

Abstract: Disclosed is a vapor axial deposition apparatus. The vapor axial deposition apparatus includes a first torch, a second torch, a temperature measuring unit and a controller unit. The first torch deposits soot on a distal end of a soot preform aligned with a vertical axis to thereby grow a core. The second torch deposits soot on an outer circumferential surface of the core to thereby grow a clad. The temperature measuring unit detects the temperature distribution of an end portion of the soot preform along the vertical axis. The controller unit determines first and second relative maximum temperatures T1 and T3, and relative minimum temperature T2 between T1 and T3 in the detected temperature distribution, and controls T1 to be within a predetermined range and the greater one of the difference (T1?T2) and (T3?T2) to not exceed a predetermined temperature.