Manufacturing apparatus and manufacturing method for optical fiber porous preform

A manufacturing apparatus for an optical fiber porous preform, the manufacturing apparatus comprising:

• a reaction chamber, having an air inlet and an exhaust duct, configured to accommodate a starting material;
• at least one main burner provided in the reaction chamber, the at least one main burner being configured to be supplied with a source gas and a flammable gas, such that particulates are to be generated from reaction of the source gas and the flammable gas and deposited on the starting material, the at least one main burner being made to repeatedly reciprocate along a longitudinal direction of the starting material;
• at least one auxiliary burner configured to be directed toward an end portion of the starting material on which the particulates are to be deposited;
• and
• an airflow guide provided on an upstream side of each of the at least one auxiliary burner to prevent an airflow flowing from the air inlet to the exhaust duct from directly blowing against the at least one auxiliary burner, the airflow guide being open on a flame emission side thereof such that the at least one auxiliary burner emits a flame, and having a shape covering, with respect to the at least one auxiliary burner, a side opposite to the flame emission side, and lateral sides as viewed from the flame emission side in their entirety, wherein
• the at least one auxiliary burner is located closer to the end portion of the optical fiber porous preform than the at least one main burner, the at least one auxiliary burner is configured to be immovable with respect to the starting material, the at least one auxiliary burner is inclined with respect to a longitudinal direction of the optical fiber porous preform so as to face a preform shape of the end portion of the optical fiber porous preform, the at least one auxiliary burner is configured to be supplied with the flammable gas, the source gas is not supplied to the at least one auxiliary burner, and a flame of the at least one auxiliary burner is positioned at an inclined part at an end part of the optical fiber porous preform where a diameter of the optical fiber porous preform is decreased to a direction of the end part in an axial direction of the optical fiber porous preform.