Abstract: Optical connector includes a circuit board, a photoelectric element, a driver chip, a coupler, and a holder holding an optical fiber. The circuit board includes a substrate having a first surface and an opposing second surface and a circuit portion formed on the substrate. The substrate defines a receiving groove in the second surface and a through hole passing through a bottom surface of the receiving groove and the first surface. The photoelectric element and the driver chip are positioned on the bottom surface, and the photoelectric element aligns with the through hole. The coupler is positioned on the first surface and aligns with the photoelectric element through the through hole. The holder is supported on the first surface and connected to the coupler. The coupler optically couples the optical fiber with the photoelectric element.

Abstract: An optical fiber coupling connector includes a circuit board, light-emitting modules, light-receiving modules, an optical coupling module, a receiving member, and optical fibers. The optical coupling module includes a main body and converging lenses. The main body has a first optical surface, a second optical surface perpendicular to the first optical surface, and a reflection surface oblique relative to the first and second optical surfaces. The converging lenses are formed on the first optical surface and are aligned with the light-emitting modules and the light-receiving modules. The receiving member includes a front end portion and a rear end portion at opposite sides and defines through holes extending from the front end portion to the rear end portion. The receiving member is coupled with the main body, and the front end portion faces the second optical surface. The optical fibers are received in the through holes.

Abstract: A multi-core fiber includes an even number of six or more of cores and a clad that surrounds the outer circumferential surfaces of the cores. The cores are formed of two types of cores and in which an effective refractive index difference in a fundamental mode is 0.002 or less in a predetermined range or more that the effective refractive index difference in the fundamental mode is varied according to a core pitch. Two types of the cores are alternately and annularly disposed at regular spacings. A difference in the mode field diameter of light propagating through the cores is 1 ?m or less.