The Multi-Physics Utility™ is designed to be used in conjunction with any of RSoft's passive device simulation tools. It provides a convenient interface from which perturbations of the refractive index profile of a structure may be included in the simulation. These perturbations can be caused by advanced physical processes in the material, such as electro-optic effects, thermo-optic effects, stress-optic effects (i.e., strain), and carrier-induced effects. All material parameters needed to describe these effects can be defined in RSoft's Material Library.
 The basic Multi-Physics Utility with electro-optic and thermo-optic effects is included with all passive device tools; the stress and carrier effects are offered as options that are licensed separately.