| 摘要 |
In the prior art, the number of intersections is 0 and the intersection loss is 0 for Port1→Port1A, and the loss is therefore estimated to be 3.2 dB as a combination of theoretical loss and excess loss. For Port1→Port1B, the number of intersections is seven and the intersection loss is 0.35 dB, and the loss is therefore estimated to be 3.55 dB as a combination of theoretical loss and excess loss. There is thus a large variation in loss per port, and a large maximum loss of 3.55 dB. The present invention is configured so that the branching ratio of each optical splitter differs in accordance with the difference in the number of intersections in each branched waveguide. The branching ratios (totaling 100%) of the optical splitters are adjusted so that the branching ratios on the high side as to the number of intersections is high in comparison with the branching ratios on the low side as to the number of intersections, and it is thereby possible to level the total loss. |
