Abstract

We present preliminary results of a study of the optical wavelength dependence on the switching voltage of an integrated optical Mach-Zehnder interferometer. The optical wavelength dependence of the operational characteristics of integrated optical components is important since future telecommunications systems are expected to be extremely broadband. The switching voltage is of particular present interest because it is quite costly at high speeds, and thus its minimization is a high priority. To effect a broadband minimization, however, we need to understand fully the factors that contribute to the wavelength-dependent changes in the switching voltage. To this end we measured the optical wavelength dependence of the switching voltage of a titanium-indiffused lithium niobate Mach-Zehnder interferometer. The measurements were made from 1.2 to 1.7 μm using a white light system with a tungsten-halogen light source. The measured switching voltage (or voltage-length product) was verified to be a supralinear function of wavelength. We modeled this wavelength dependence by calculating the overlap between the optical and modulating electric fields. These calculations were made using a parameterfree variational finite-difference approach. We found the calculated wavelength dependence to be the same as that found experimentally.

© 1987 Optical Society of America