AbstractA rugged flexible hollow-fiber waveguide that permits preservation of good transverse spatial coherence of input infrared laser radiation and that transmits substantial power of such radiation, with low attenuation. The present invention preferably comprises a small-diameter thin-wall silica-glass tube; a protective coating on the outer surface of the tube; a sufficient reflective layer on the inner surface of the tube; and a thickness, optimal for the wavelength(s) of interest, of dielectric on the exposed surface of the reflective layer. The fiber is manufactured with processes that maintain the smoothness of the bore. In addition to transmitting mid-infrared laser radiation through the bore of the flexible hollow-fiber waveguide, a second beam may be transmitted through the annular body of the flexible hollow-fiber. The second beam may comprise an aiming beam which creates a ring pattern surrounding the infrared beam, or the second beam may be a second therapeutic beam in the visible or near infrared region.