| 摘要 |
PROBLEM TO BE SOLVED: To provide a fiber welded type optical coupler that enables an accurate branching ratio to be obtained even in need of increasing the branching ratio for the coupler. SOLUTION: The clad 1b of a first single mode fiber 1 and the clad 2b of a second single mode fiber 2 having a greater loss than the first are partially arrayed and adhered closely with each other then, by heating and drawing the close adhesion part, both single mode fibers are welded together. |
