公开(公告)号：US12019267B2

公开(公告)日：2024-06-25

申请号：US17627866

申请日：2020-07-21

申请人： NIPPON TELEGRAPH AND TELEPHONE CORPORATION

发明人： Taiji Sakamoto ,  Kazuhide Nakajima ,  Takashi Matsui ,  Kyozo Tsujikawa ,  Kunimasa Saitoh ,  Takeshi Fujisawa

IPC分类号： G02B6/02 ,  G02B27/00

CPC分类号： G02B6/02042 ,  G02B27/0012

摘要： An object of the present invention is to provide a multi-core optical fiber that can prevent an increase in bending loss even when a distance between a peripheral core and a cladding boundary is decreased, and can improve a bending loss characteristic in a state where an influence on a cutoff wavelength and a mode field diameter is small, and a design method thereof.
The multi-core optical fiber according to the present invention is an optical fiber in which two or more core regions are arranged in a cladding region having a refractive index lower than a refractive index of the core at a minimum core interval, a ring-shaped low refractive index region surrounding the core and having a refractive index lower than the refractive index of the cladding region is provided, a bending loss after the provision of the ring-shaped low refractive index region is reduced as compared with a characteristic in a case where the ring-shaped low refractive index region is not provided, and at the same time, a change in mode field diameter after the provision of the ring-shaped low refractive index region is not changed as compared with a characteristic in a case where the ring-shaped low refractive index region is not provided.