| 摘要 |
Provided is a multicore fiber capable of suppressing a cutoff wavelength of a specific core from increasing while reducing inter-core crosstalk. A multicore fiber 100 includes a cladding (40) and a plurality of core elements 10b (23a) which is provided in the cladding 40 and includes a core 11 (21), an inner cladding layer 12 (22) that surrounds the core 11 (21), and a low-refractive index layer 13b (23a) that surrounds the inner cladding layer 12 (22) and has a lower average refractive index than the cladding (40) and the inner cladding layer 12 (22). The plurality of core elements 13b (23a) is arranged such that a specific core element 13b is surrounded by three or more core elements 23a, and a low-refractive index layer 13b of a partial core element 10b of the plurality of core elements 13b, 23a is configured to have larger light confinement loss in the core 11 than low-refractive index layers 23b of the other partial core elements 20a. |
