Patent ID: 9726816
Date: 2017-08-08
CPC Classifications: G02B

Claim:
1. A multi-core optical fiber comprising: eight or more core units each having a core, an inner cladding surrounding the core, and a trench surrounding the inner cladding; a common cladding individually surrounding each of the eight or more core units; and a resin coating surrounding the common cladding, wherein each of the cores, each of the inner claddings, each of the trenches, and the common cladding are comprised of silica-based glass, wherein a diameter of the common cladding is not more than 126 μm, wherein when relative RI differences of each core, each inner cladding, each trench, the common cladding, and the coating with respect to a predetermined RI are defined as Δ1, Δ2, Δ3, Δ4, and Δ5, respectively, each core, each inner cladding, each trench, the common cladding, and the coating satisfy the following conditions: wherein optical characteristics of each core are as follows: a transmission loss is not more than 0.5 dB/km or not more than 0.4 dB/km at a wavelength of 1310 nm; a mode field diameter a bending loss in a bending radius of not less than 5 mm or in the bending radius of not less than 3 mm and, less than 5 mm is not more than 0.25 dB/tum at the wavelength of 1310 nm; a zero dispersion wavelength is from 1300 nm to 1324 nm; a cable cutoff wavelength is not more than 1260 nm; and an inter-neighboring-core crosstalk between a concerned core, out of the cores, and a core neighboring to the concerned core or a secondary inter-neighboring-core crosstalk between the concerned core and another core neighboring to the core neighboring to the concerned core is not more than 0.001/km at the wavelength of 1310 am.