An optical fiber assembly comprising an optical fiber casing and optical fiber deployed within and fixed relative to the casing at multiple fixation points spaced along the casing. The optical fiber assembly includes one or more weights attached within the casing to the optical fiber, for increasing a tension of the optical fiber between the multiple fixation points; flexible portions and rigid portions, with the optical fiber fixed to the flexible portions; and/or at least one guide member positioned at at least one of the fixation points and configured to constrain a bend radius of the optical fiber.