OPTICAL PART AND ITS MANUFACTURING METHOD

摘要

PROBLEM TO BE SOLVED: To provide an optical part and an method for manufacturing the optical part wherein a micro-bend loss is controlled and transmission characteristics are stable. SOLUTION: In the optical part P, an optical fiber coil 81 is housed in a housing casing 80. The fiber coil 81 is composed by winding an optical fiber 32 in a coil shape and is set in the coil bundle state that the wind distortion is substantially released. A filler 84 is filled in the housing casing 80 in the state that it comes into direct contact with the outer periphery of the optical fiber 32 so as to enclose the optical fiber 32. The filler 84 is made of thermosetting or ultraviolet ray setting silicone resin or the like and consists of a substance in which weight-concentration of a Na+ ion and a K+ ion (ionic impurities of a positive ion) determined by the whole resolving method is 0.1-6 ppm and also weight-concentration of Cl- ion (ionic impurities of a negative ion) determined by the whole resolving method is 0.5-10 ppm.