EVALUATION OF SOME FIBER OPTICAL WAVEGUIDES FOR ASTRONOMICAL INSTRUMENTATION

Fused silica optical fibers were examined with a view toward use in fiber-coupled spectrographs. The emphasis of the investigation was on how well the input focal ratio was preserved during transmission down a long fiber. The best overall performance was given by the Galite 4000 series and the Maxlight 150 micron fibers. The Valtec products also yielded good results when cabled so that stress could not be easily induced. It was found that the smaller fibers yielded better performance with respect to focal ratio preservation.