Digital holographic interferometric phase shifting method is used to calculate the refractive index profile of
graded index (GRIN) optical fibre and the 3D refractive index distribution across the GRIN fibre. GRIN optical fibre
sample is immersed in a suitable liquid and then Mach-Zehnder-like arrangement phase shifting digital holographic
system is used. The optical phase difference due to the graded index optical fibre can be extracted by digital holographic
interferometric phase shifting technique. The problem of the tilted GRIN optical fibre with respect to the reference axis
is solved, since the fibre must be perpendicular to the reference axis according to symmetry considerations. The optical
phase difference map along the GRIN optical fibre is used to calculate the mean values of the optical phase difference
across the fibre. The refractive index profile of GRIN optical fibre is calculated using the multilayer mathematical
model, where the refraction of the incident rays through the fibre layers is considered. The shape parameter of the
investigated optical fibre is determined. The mode field distributions can be analyzed for the used GRIN optical fibre.
The calculated refractive index profile is used to reconstruct the 3D refractive index distribution across the fibre sample.
The optical- functional properties of an integrated-optical strip-waveguide in a planar polymer chip are presented in this
article. The waveguide was directly written into the surface of a planar polymer chip by UV-laser irradiation. Digital
holographic interferometric phase shifting method is used to calculate the refractive index profile of the waveguide. This
profile contains one or two zones according to the parameters of UV-laser. The mode field distribution and the effective
mode indices for each zone are obtained. The study shows that the optical-functional properties strongly depend on the
UV-irradiation parameters. Several mostly independently occurring photochemical processes competing with one
another are proposed to explain the formation and shape of the refractive index distribution.