Alberucci, A.A.AlberucciJisha, C.P.C.P.JishaNolte, S.S.Nolte2022-03-142022-03-142019https://publica.fraunhofer.de/handle/publica/40643810.1109/CLEOE-EQEC.2019.8872199The determination of the index profile in guiding structures is a central problem in applied photonics, ranging from optical fibers to femtosecond-written waveguides [1]. A non-destructive and relatively easy method consists in the measurement of the index profile by measuring the transmitted field [2]. From the transmitted field, the refractive index profile is computed by direct inversion of the Helmholtz equation. This technique is called near-field method. Here we present a new near-field method based upon the inversion of the overlap integral.en620conference paper