Mapping method for the comparison of mode data from field assisted ion diffused guides

It is shown that the mode data of field assisted ion exchange profiles in glass can be mapped onto one another when the refractive index profiles are shifted versions of each other, i.e. of the form n(x + s) where s is a shift distance. This allows the mode data of shallow guides to be compared with data of deeper guides. The mapping has utility in that the shallow guide may not support a sufficient number of modes in order for a refractive index profile reconstruction to be made.