| 摘要 |
PROBLEM TO BE SOLVED: To provide a conversion element that can suppress the characteristic deterioration of a multicore optical fiber when the multicore optical fiber and an optical element are optically coupled to each other.SOLUTION: A conversion element 10 optically couples a multicore optical fiber 80 with a planar optical waveguide 90 to each other, and includes a multicore optical fiber side conversion element 11 and a planar optical waveguide side conversion element 12. There is a gradual change in each of a light incidence/emission gap (grating coupler gap) of the planar optical waveguide 90, a core gap on the cross section of the planar optical waveguide side conversion element 12, a core gap on the cross section of the multicore optical fiber side conversion element 11, and a core gap on the cross section of the multicore optical fiber 80. The multicore optical fiber side conversion element 11 and the planar optical waveguide side conversion element 12 are respectively fixed, being bent. |
