A fiber optic laser conducting probe is used for photodynamic therapy. In this fiber optic laser conducting probe, an optical fiber has an end used for conducting a pulse laser beam. The laser beam is conducted through the optical fiber and irradiated from the end. A end tip is made of polyamide resin. The end tip has a hollow portion, and is attached to the end of the optical fiber such that the pulse laser beam can be irradiated through the end of the optical fiber, through the hollow portion and through the end tip.

An illumination device comprises a light source like a halogen lamp, a light guide, a round rod-shaped transparent radiation member having a proximal end and a distal end, and a transparent radiation plate. The light guide is a plastic optical fiber comprising a single core of silicon rubber and a cladding layer of tetrafluoroethylene/hexafluoropropylene copolymer. The radiation member is a transparent circular cylinder made of acrylic resin, and has a predetermined pattern of light scattering regions on its surface oppose the directions where the light is radiated. The radiation plate is placed such a position that one side plane of the radiation plate oppose to he radiation member, and also has a predetermined pattern of light scattering regions on the back. The light scattering regions are provided along said radiation member in such a way that a ratio of an tea of one region to that of adjacent region becomes larger as the one region becomes distant from the proximal and of the radiation member.

Illumination devices (20, 20', 20", 20'") for delivering ultraviolet light to an in vivo treatment site comprise an optical fiber (22) having an illumination window (40, 40', 40", 40'"). A circumferential contour (46, 46', 46", 46'") of the core is shaped along the illumination window so that, for an internally reflected ray travelling in the core, the internally reflected ray has differing angles of incidences along the illumination window. In addition, the contour of the circumferential core causes rays travelling parallel to a major axis of the optical fiber to strike the core-scattering layer interface, thereby resulting in greater irradiance. In one embodiment, in the illumination window (40') a circumferential contour (46') of the core is shaped by etching to have an essentially semi-conical shape. In another embodiment, in the illumination window (40") the circumferential contour of the core has a plurality of circumferential segments (46a", 46b", 46c"), one of which has an essentially semi-conical shape and another of which has a reduced radius annular shape. In another embodiment, a reflective surface (60) is formed at a distal end of the optical fiber. An optical scattering material (48, 48', 48") is formed over the fiber core in the illumination window. The optical scattering material is preferably an admixture of optical epoxy and Al.sub.2 O.sub.3.

A diffusing optical fiber tip yielding a homogenous output pattern having a total illumination angle of at least 180 degrees. The diffusing optical fiber tip has an outer diameter which is no greater than that of the optical fiber, and appears as a point source of illumination, having substantially the same output pattern when immersed in water as it does in air. The diffusing optical fiber tip is manufactured on the end of a typical acrylic optical fiber by causing longitudinal stresses in the fiber end, which are then relieved by forming axial cracks in the fiber core at the optical fiber tip. As a result, light exiting the optical fiber must traverse a scrambled pathway caused by a complex interaction of reflections and refractions, yielding wide angle diffuse illumination.

An optical hot tip and method for manufacturing the same. The hot tip is for conducting high optical power beams at the tip of a fiber or waveguide. The light from the fiber or waveguide is absorbed in and end tip in order to generate heat. The heat can then be used in a variety of applications.