| 摘要 |
PROBLEM TO BE SOLVED: To provide a Y branching circuit having a small excessive loss and superior reproducibility, and also to provide its manufacturing method. SOLUTION: The Y branching circuit of the present invention is equipped with a lower clad (10), a circuit core (16) composed of the main core (13) formed on the lower clad and two branching cores (14, 15) core-connected to the main core, and an upper clad (11) in which the circuit core is imbedded. The main core and the two branching cores are connected with a space (18) apart. The two branching cores have a ratio of a width to a height ranging 50 to 150% and have a gap (17) which is narrower in the upper clad side than in the lower clad side in the end on the main core side. The gap between the two branching cores is deformed to make the upper clad side narrower in a progression of covering the circuit core with the upper clad. The softening temperature is lower than that of the core by 100-250°C, and the processing is performed at a temperature of 50-200°C higher than at the softening temperature of the core. COPYRIGHT: (C)2007,JPO&INPIT |
