Abstract

The refractive index profiles of titanium-diffused LiNbO₃ planar and channel waveguides are determined directly by measuring the reflectivity of angular polished surfaces. Three measurement techniques are described and compared: (1) large area illumination of the angular polished waveguide and imaging of the reflected light to a vidicon, (2) scanning of a focused beam across the sample, and (3) scanning of the sample under a focused beam. Preference is given to the last method which provides an accuracy of Δn/n = 10⁻⁴ with a local resolution of the index profile of <0.1 μm in depth and ~1 μm in width.

© 1990 Optical Society of America

Refractive Index Profile Measurements of Diffused Optical Waveguides

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