| 摘要 |
An optical fiber includes a core portion and a cladding portion that is formed around an outer periphery of the core portion and has a refractive index lower than a maximum refractive index of the core portion. As characteristics at a wavelength of 1550 nm, an effective core area in a fundamental propagation mode is 120 µm 2 or larger, an effective core area in a first higher-order propagation mode is 150 µm 2 or larger, an effective core area in a second higher-order propagation mode is 180 µm 2 or larger. An effective refractive index in the second higher-order propagation mode is larger than the refractive index of the cladding portion by 0.0002 or more, and an effective refractive index in a third higher-order propagation mode is less than the refractive index of the cladding portion. |
