Patent ID: 11899237
Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Field: Optics (Instruments)
Classification: CPC G  H | IPC G

Claim 0:
1. A multicore optical fiber comprising:
four cores having a radius a1 disposed in a longitudinal direction in square lattice shape;
first cladding regions disposed around each of the cores and having a radius a2 with a refractive index lower than a refractive index of the cores, a specific relative refractive index difference to the cores being Δ1; and
a second cladding region disposed on an outer periphery of the first cladding regions and having a refractive index higher than the refractive index of the first cladding regions and lower than the refractive index of the cores, a specific relative refractive index difference to the core being Δ2, wherein
an outer diameter of the second cladding region is 125±1 μm,
an effective cross-sectional area at a wavelength of 1550 nm is 80 μm2 or more,
bending loss at a wavelength of 1625 nm and a bending radius of 30 mm is 0.1 dB/100 turns or less, and
a cutoff wavelength is 1530 nm or less.