Abstract

Gradient index (GRIN) rod lenses with parabolic index profiles have a variety of application including imaging systems and optical communication systems.¹⁾ There are a number of techniques that could be used for making these radial gradients in the glass. Ion exchange is probably the most widely and successfully used technique in the fabrication of GRIN rod lens for optical communication applications, because it is the simplest in terms of instrumentation and control. In conventional ion exchange techniques, T1 ions in a glass rod are exchanged for K or Na ions in a molten salt.^2,3) There appears to be some problems in T1 ions, namely high toxicity and low diffusion rate in the glass. Ag ions also offer great potential for making large numerical aperture lenses because of their high refractive index in the glass. However, silver oxide cannot be introduced into the glass in significant quantities by melting.

© 1987 Optical Society of America