Side-emitting optical fibers for lasers with orientation markings

A side-emitting optical fiber is provided. The side-emitting optical fiber has a proximal end for receiving radiation, a distal end including a distal tip through which the radiation is emitted in a direction laterally of the longitudinal axis of the fiber via a radiation exit regions at the distal tip, and a visually discernible marking. The visually discernible marking is adjacent to the radiation exit region to enable discerning the location of the radiation exit region as the optical fiber is manipulated by a user. The side-emitting optical fiber is characterized in that the visually discernible marking extends for approximately 180 DEG around the circumference of the fiber, has a visually discernible center located approximately 180 DEG radially from the center of the radiation exit region, and has visually discernible opposed axially-extending edges each of a length having a known predetermined relation to the axial distance between a known predetermined point of the marking and the center of the radiation exit region. The arrangement is such that at least one-half the marking, including its center and one of its axially-extending edges, is viewable to the viewer in all orientations of the fiber where the radiation exit region faces away from the user, and thereby enables the user to visually discern both the radial location and the axial location of the center of the radiation exit region.