| 摘要 |
A leakage light removal structure 70 is used to remove leakage light in an optical fiber 140 having a core 160, a cladding 162 having a refractive index lower than the core 160, and a covering material 164 having a refractive index higher than the cladding 162. The leakage light removal structure 70 has a fiber housing 72 that houses part of the optical fiber140, a covering material extension portion 175 covering part of a whole circumference of the cladding 162 by extending part of the covering material 164 along a longitudinal direction of the optical fiber 140 within the fiber housing 72, and a cladding exposure portion 174 in which a portion of the whole circumference of the cladding 162 other than the covering material extension portion 175 is exposed within the fiber housing 72. The covering material 164 may be covered with a resin 76 having a refractive index not more than the refractive index of the covering material 164. For example, the covering material extension portion 175 is formed with a range of angles equal to or less than 180° about an axis of the optical fiber 140 in a cross-section perpendicular to the axis. |
