Abstract

The voltage-dependent transfer characteristics of multimode slab waveguide electrooptic filters have been examined analytically in considerable detail, with special attention to the roles played by differential modal phase delays, modal dimensionality, and attenuation. This work has been motivated by attempts to achieve a more satisfactory match between some early experimental results and our computer simulations based on a multimode coupled-mode formalism.¹ An important determination is the minimum number of modes (minimum dimensionality) that will allow a reliable representation of the model. We find that a dimensionality of 10 is essentially adequate for the device modeled, having a thickness of ~130 μm, operating near 0.475-μm wavelength. In addition, we find that inclusion of an initial dead length, with the attendant dephasing of modes, is an important factor in specifying appropriate modal input conditions to achieve an improved agreement with the experimental data. Suitable allowance for attenuation, particularly of the TM polarization component, also aids in improving this match.

© 1986 Optical Society of America