CORE WIRE OF OPTICAL FIBER

摘要

PROBLEM TO BE SOLVED: To provide an SM-type optical fiber core wire small in a connection loss and provided with a non-releasable thin layer. SOLUTION: On an SM-type optical fiber 13, a non-releasable thin layer 14 is formed so that the finished diameter is 125μm and the decentering value (a) of a core 11 to the finished diameter is not exceeding 1. The non-releasable thin layer 14 is a synthetic resin having a Young's modulus of 50-250 kg/mm2 at a room temperature and good adhesiveness to a clad 12 of the optical fiber. Further, a protective coating layer 17 having a double layer structure is formed on the non-releasable thin layer 14 by successively coating a primary coating film 15 comprising a synthetic resin having, e.g. a Young's modulus of 0.01-0.5 kg/mm2 at the room temperature and then, a secondary coating film 16 comprising a synthetic resin having a Young's modulus of 10-200 kg/mm2 at the room temperature on the primary coating 15.