| 摘要 |
A cylindrical bobbin (11) having flanges (11B) at both ends thereof is formed as a unitary structure with them, using a material of thermal conductivity nearly equal to or lower than that of an optical fiber coil (12), and the optical fiber coil is wound on a housing portion (11C) defined by the flanges therebetween. An annular member (15) is mounted on the bobbin to cover the housing portion on the outside of the optical fiber coil, forming an annular case (14) for housing the optical fiber coil, together with the bobbin. The annular member is also made of a material which has a thermal conductivity nearly equal to or lower than that of the optical fiber coil. <IMAGE> |
