CONNECTING DEVICE FOR OPTICAL FIBER

PURPOSE:To evaluate a connection loss with high precision and to improve the reliability of the alignment of an optical fiber by providing a transmissive body which is coupled with a photodetecting element to the V-groove bottom part of an alignment block. CONSTITUTION:Transmissive bodies 18 and 19 whose end parts are coupled with photodetecting elements 22 and 23 are buried in bottom parts of V-groove parts 12a and 13a of alignment blocks 12 and 13 having the V-groove parts 12a and 13a where end parts of optical fibers 6 and 7 are positioned and fixed. Then, part of transmitted light is photodetected as bent light through the transmissive body 18 at the bottom part of the light-source side V-groove part 12a. Further, part of the quantity of light incident on a clad part due to a defect in the positioning of the optical fiber as to the quantity of light propagating to a connection part is photodetected through the transmissive body 19 at the bottom part of the V-groove part 13a.