Optical fiber structures having at least two cores, whether unitary or separable, may be fabricated by controlling the placement of the cores prior to final processing to make the multi-core fiber structure. When the fiber is to be separable, at least two performs are attached, and the attachment height between adjacent canes is controlled to allow separation to be realized (or attachment to be maintained there between) anywhere along the separable multi-core fiber. These canes are then drawn together to form a desired composite fiber, either or both ends of which may be separated to allow for individual manipulation of fiber ends. The separable multi-core fiber may be utilized to fabricate a dual-port or multi-port optical component in which an input and an output (or multiple input/output) fibers are attached to the component, and the exposed distal ends of the separable multi-core fiber are thereafter separated from one another (even after the entire device is assembled and packaged) to provide separated waveguides for pigtailing or splicing to input or output fibers (or other planar or micro-optic components).