An optical device for illuminating the vasculature of a mammal using ultraviolet and visible light is described. The optical device includes an optical fiber encased in a biocompatible sheath, and is dimensioned to lie within an intravascular catheter. When placed within a vascular space and coupled with a suitable light source the optical device illuminates the vascular space and its contents. The faces of the optical fiber are configured to optimize the capture of ultraviolet and visible light from a light source without the use of active optics.
