MEASUREMENT OF OPTICAL FIBER STRUCTURE

摘要

PURPOSE:To measure the structure of an optical fiber, by making light transmitting through a liquid filled between an optical fiber to be measured and a transparent tube with the refractive index slightly higher than those of a clad of the optical fiber being measured and the transparent tube to observe it through a transparent plate. CONSTITUTION:An optical fiber 1 to be measured has a tip face 6 which is cut at a right angle to the axis thereof. The tip part 8 thereof is cleared of a cover layer 7 over a fixed length. A transparent plate 3 is arranged vertical to a transparent tube 2 ahead of the front end of the transparent tube 2 with the inner dia. larger than the outer dia. of a clad layer of the fiber 1 and the tip part 8 is inserted into the transparent tube 2. A liquid 4 with the refractive index slightly higher those of the clad of the fiber 1 and the transparent tube 2 is filled between inside the transparent tube 2, between the transparent tube 2 and the transparent plate 3 so that it infiltrates into the tip part 8. Light is projected into the liquid 4 from another optical fiber 5 or light is made to propagate from the fiber 1 itself to observe a end face 6 through the transparent plate 3. In this manner, the outer dia. of the fiber 1 or core shape and the light intensity distribution in the propagation mode can be measured.