Characterizing fiber-optic illuminators for lighting applications

This manuscript describes methods for evaluating fiber-optic illuminators. In an initial study, several 150-watt commercial fiber-optic illuminators were tested for system efficacy. The illuminators were tested with a I-foot reference fiber optimized for the particular illuminator as supplied by the respective manufacturer. The variations in fiber sizes and configurations made comparative evaluation between systems more difficult. Furthermore, one data point per system doesn't provide sufficient information about the illuminator. Alternatively, two sets of standard fibers were utilized to evaluate fiber-optic illuminators that had a common single port configuration and size. The data generated with the fiber sets was useful for developing a family of plots showing the flux, flux density, and color variation as a function of fiber diameter. This method eliminates premature judgement of illuminator performance on only one measurement with one fiber diameter. Finally, the use of a CCD camera was evaluated for characterizing the beam of a reflectorized lamp, typically used in a fiber-optic illuminator. A low-wattage reflectorized metal halide lamp was used in this section of the study. The amount of flux available for coupling into a given size fiber and the fiber location for optimum light coupling were estimated using the CCD camera. The results obtained thus far show that the CCD camera is a useful tool for characterizing fiber-optic illuminators.