A beam-shaping optical system suitable for use with optical coherence tomography includes a sheath defining a central cavity having an inner wall, an optical fiber positioned within a ferrule, the ferrule configured to mate with the inner wall of the sheath, and a beam-shaping insert positioned within the sheath and configured to mate with the inner surface of the sheath. The beam-shaping insert defines a beam-shaping element. The optical fiber is configured to emit an electromagnetic beam toward the beam-shaping element and the beam-shaping element is configured to reflect the electromagnetic beam externally to the beam-shaping insert.