PURPOSE: To make coatings thinner while maintaining transmission characteristics by including at least first and second coating layers and composing this second coating layer of a resin having micronecking resistance.
CONSTITUTION: This coated optical fiber is composed of a glass fiber 1 for light transmission, the first coating layer 2 formed on the outer circumference of this fiber 1 and the second coating layer 3 formed on the outer circumference of the first coating layer 2. The glass fiber 1 for light transmission is usually composed of a core 2 and a clad formed on the outer side of this core. The second coating layer 3 consists of the resin having the micronecking resistance. Whether the resin has the micronecking resistance or not is more specifically discriminated by a test for ascertaining the microcracking resistance. Then, the coated optical fiber having a good pressure characteristic to a fiber side and/or pressure characteristic to a bobbin side is obtd. even if the outermost layer coating is made hard (by increasing its Young's modulus).
AKASAKA NOBUHIRO
TSUNODA TATSUYA
MATSUDA HIROO
