Abstract Ionic exchange techniques have been applied to multicomponent indium-based fluoride glasses in order to develop a gradient index structure having the properties of a planar optical waveguide. Several molten salts have been tested with the aim of exchanging Na+ by Li+ or K+. When the melt is an Li+-rich organic salt and when the glass sample contains about 15% Na+, the formation of a gradient index profile is characterized by ‘m-lines’ experiments. Depending on time and temperature of immersion, one, two or three modes of propagation have been detected in this new generation of waveguides. They are potential candidates for active and passive integrated optics operating in the visible and mid-infrared.