| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical fiber coupler which branches and couples light with directivity and its manufacture. SOLUTION: The coupler 2 is equipped with an optical fiber part 21 for a trunk line and an optical fiber part 22 for a branch line. Those optical fiber part 21 and optical fiber part 22 are joined together by an ultrasonic welding method while being held linearly so that the optical fiber part 22 for the branch line has a specific curvature. By this ultrasonic welding method, the core 22a of the optical fiber part 22 for the branch line is exposed and the clad 21b of the optical fiber part 21 for the trunk line and the core 22a of the optical fiber part 2 for the branch line are joined together. Here, the clad 21b of the trunk-line optical fiber part 21 and the core 22a of the branch-line optical fiber part 22 are formed out of the same material to make the entry of light into the trunk line optical fiber part 21 from the branch-line optical fiber part 22 efficient and irreversible. |
