A new technique for the preparation of low-loss and graded-index optical fibers

The lowest loss optical waveguides to date are those of high silica composition prepared by vapor deposition. The present article describes a method for producing waveguides having a GeO
2
-SiO
2
core and SiO
2
cladding. These combine low loss with relatively large index differences between core and cladding, Large index differences create problems in optical communication systems because of dispersion effects. Means of index grading so as to decrease dispersion are also described.