Index profile reconstruction of fiber preforms from data containing a surface refraction component

In a rigorous mathematical sense, conventional index profile reconstruction methods are only applicable to data which do not contain a surface refraction component. In practical profiling work, however, it may not always be possible or even practical to maintain a perfect index match at the preform-liquid interface and, as a result, one may have to work with data containing a significant surface refraction component. A new profile reconstruction method is introduced which is applicable in this situation. The capabilities as well as limitations of this method are demonstrated by using it to reconstruct index profiles from simulated refraction angle data. It is shown that the new method is far superior to conventional ones in reconstructing profiles from transverse data containing a surface refraction component as long as accurate data for grazing and near grazing incident beam positions are available.