HOLE ASSIST TYPE HOLEY FIBER AND LOW BENDING LOSS MULTIMODE HOLEY FIBER

摘要

A high-performance HAHF that achieves both low bending loss LB and a short cut-off wavelength λC is obtained. The fiber is a hole-assisted holey fiber including a core region; a cladding region around the core region, the core region having a higher refractive index than that of the cladding region; and a plurality of holes that are provided in the cladding region around the core region, wherein the holes form two layers comprising an inner hole layer and an outer hole layer, the inner hole layer has the same number of holes as the number of the holes in the outer hole layer, the outer holes are provided in locations in which holes are absent when viewed from the center of the core region, holes in each layer forming a respective form layer have the same diameter, a distance Λ1 from a center of the core region to a center of an inner hole and a distance Λ2 from the center of the core region to a center of an outer hole satisfy Λ1, Λ2, and a diameter d1 of an inner hole and a diameter d2 of an outer hole satisfy d1 ≤ d2.