PURPOSE: To easily manufacture a base material of an arbitrary size for an optical fiber by coating the inside of a tubular member with liq. starting material composed of metallic compounds and forming a glass soot layer on the inside by microwave heating.
CONSTITUTION: Desired organometallic compounds in a storage tanks 5 for liq. starting material are blended in mixing tank 3 to prepare liq. starting material, and this material is sprayed on the inside of tubular member such as quartz tube 1 made of a thermoplastic material from nozzle 2 with an inert gas from gas feed source 4 to form a liq. starting material layer 7. Layer 7 is then irradiated with microwaves from microwave heater 6 in an oxidizing atmosphere to form a glass soot layer 9. The resulting base material for an optical fiber is collapsed by an ordinary method and heat drawn to obtain an optical fiber of a desired diameter.
YAMAZAKI TETSUYA
IKUMA TOSHIROU
