Apparatus and method for making an optical fiber preform using a correction pass

An apparatus for making an optical fiber preform, which comprises:

• means for fixedly holding a rod-shaped core and capable of rotating the rod-shaped core;
• a partial traverse shaft which is arranged in parallel to the rod-shaped core, has a plurality of oxyhydrogen flame burner units fixed thereon, and is capable of moving the plurality of burner units along the lengthwise directions of the rod-shaped core so that fine particles of glass from the plurality of oxyhydrogen flame burner units are deposited on the rod-shaped core at a given length thereof;
• an overall traverse shaft which is arranged in parallel to the rod-shaped core, and has monitoring means for detecting a deposited amount of the fine particles on the rod-shaped core along the lengthwise direction thereof;
• and
• another overall traverse shaft which is arranged in parallel to the rod-shaped core and is kept apart from the partial traverse shaft, and has at least one burner unit capable of moving along the lengthwise directions of the rod-shaped core to correct the deposited amount based on the results of the detection of the monitoring means.