Three-dimensional characterization of the light distribution from diffusing cylindrical optical-fiber tips.

A rapid and sensitive technique for quantitatively examining the three-dimensional light distribution from optical-fiber diffusers for photodynamic therapy applications was developed. We have used this system to evaluate the longitudinal and azimuthal uniformity of the light output from cylindrical diffusing tips and have determined a standard detector configuration for assessing the optical quality of these diffusers. As an example of the sensitivity and the accuracy of this method, the effect of microbending of the fiber on the output intensity distribution, as well as the effect of the choice of laser used, was investigated and was seen to have a significant impact on the uniformity of these diffusers.