Patent ID: 9081129
Filing Date: 2015-07-14
Classification: G02B

Abstract:
1. A multi-core fiber comprising: an even number of six or more of cores; and a clad surrounding outer circumferential surfaces of the cores, wherein: the even number of cores are formed of two types of cores between which an effective refractive index difference in a fundamental mode is different; in the cores, the two types of cores are alternately disposed at regular spacings, and the cores are annularly disposed at an interior angle formed of lines connecting centers of the cores adjacent to each other, the interior angle being greater than an angle of 90°; a difference in a mode field diameter of light propagating through the cores is 1 μm or less; and an expression is satisfied: wherein an inter-center pitch between the cores adjacent to each other is D μm and an effective refractive index difference between the cores adjacent to each other is Δn eff .