Abstract

A program has been developed to fabricate silver film-diffused glass, optical waveguides for use as optical couplers in optical signal processing systems. The diffusion process was assisted by applying electric fields ranging from 40 to 200 V/mm and at elevated temperatures ranging from 270 to 300°C. The graded-index profiles were analyzed using the WKB method and the effective index of refraction values measured with the prism coupling technique. Results of the WKB analysis showed that a Gaussian profile fits the effective index data best. Loss measurements of around 1 dB/cm were found for wavelengths of 633 nm or longer. However, at shorter wavelengths of 488 and 514 nm losses are substantially higher and could reach several dB/cm. One mechanism proposed for this loss is the wavelength-dependent absorption by silver aggregates or silver complexes which are present in the guiding wave layer. A strong red incoherent emission is produced in the guiding-wave layer, and this radiation is emitted normal to the waveguide surface when guided wave modes are excited at 488 nm. When 514 nm is used, this emission takes on a brownish red appearance. This emission consists of broad bands with band centers that are shifted from the excitation line by wavenumber shifts ranging from 3190 to 6475 cm^-1, with 488-nm excitation and with 514-nm excitation, the shifts range from 4250 to 5320 cm^-1.

© 1987 Optical Society of America