Graded-index surface or buried waveguides have been realized by thermal or electrically induced ionic exchange in glass. Deep waveguides can be obtained up to 200 μm when Li+ ions are used. Using Ag+ ions, buried waveguides can be obtained with a maximum index at 80 μm into the substrate. Typical losses for these devices are 0.5 dB/cm. Maximum index variations can be tuned from 0 to 0.11.

Graded-index surface or buried waveguides by ion exchange in glass

A gradient index having 0.22 as maximum value has been obtained in a TiF6 Schott glass by the ion exchange technique. Index profiles and ionic concentration are presented. The reasons for such a high gradient are analyzed.

High index gradient in glass by ion exchange.

A diffusion technique for producing an inside-maximum distribution of refractive index in glass plates

A new technique is presented to realize Schmidt plates by ionic exchange controlled by electric field into adjacent areas. The shape and optical path in these areas may be adjusted very accurately. A preliminary plate has been made with three areas, and results are analyzed.

Realization of Schmidt plates by ion exchange in glass.

Future optical technologies are basically depending on and employing different types of optical waveguides. The fabrication of waveguides with different properties represents an expanding direction in both the industrial and scientific fields. In the current paper, we focus on studying the polymeric planar waveguides fabricated by the method of UV–excimer–laser lithography. We propose a general technique based on the WKB approximation and digital holographic interferometry to characterize slab waveguides with arbitrary refractive index profile. The necessary theoretical model is derived and the characterization method given in detail. Two samples are fabricated from polymethylmethacrylate (PMMA) polymeric material using different parameters for the used UV-laser. Then a phase-shifting digital holographic technique with the help of a Mach–Zehnder-like interferometer, is used to characterize the samples and measure their modified refractive index profiles. The resulting profiles are then fed to the proposed theoretical model and a full TE mode analysis is obtained. These results prove the ability of the proposed technique to analyze planar waveguides having any complicated refractive index profile.

General method based on WKB approximation and digital holography to characterize planar waveguides

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Determination of the index profile in a graded index optical waveguide : a comparaison between perturbation method and W.K.B. analysis and chemical analysis

G.H. Chartier

Papers

Determination of the index profile in a graded index optical waveguide : a comparaison between perturbation method and W.K.B. analysis and chemical analysis