| 摘要 |
PROBLEM TO BE SOLVED: To stabilize the temperature characteristics and transmission characteristics of an optical fiber unit. SOLUTION: The optical fiber unit used for an optical submarine cable comprises a plurality of coated optical fibers 20 and 20 coated with resins of a urethane acrylate UV system in two layers, packing materials 30 holding a plurality of the coated optical fibers 20 and a coating layer 40 coating the outer peripheries of the packing materials 30. The optical fiber unit is formed by coating the coated optical fibers 20, setting the Young's moduli of the coating layers so as to attainε1<ε2 andε3<ε4 and forming the coating layers so as to satisfyε1<ε3 when the Young's modulus of the resin on inner layer side of the coating 20a is defined asε1, the Young's modulus of the resin on the outer layer side asε2, the Young's modulus of the packing material 30 asε3 and the Young's modulus of the coating layer 40 asε4.
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