An optical fiber assembly includes a core. The core includes a central portion and a plurality of fins that extends radially outward from the central portion. The central portion defines a central passage. The central portion and the plurality of fins cooperatively define a plurality of grooves that is helically oriented along a length of the core. A plurality of optical fibers is disposed in the plurality of grooves. A strength member is disposed in the central passage of the core. An outer covering surrounds the core. The outer covering is air permeable.