This document analyzes the propagation of modulated optical signals in integrated optic environments. It begins by discussing how modulation distributes an optical signal's power across multiple frequency components, requiring analysis beyond the monochromatic assumption. It then models a slab waveguide numerically to show how propagation constants and mode profiles vary with frequency. Finally, it simulates the phase variations experienced by different frequency components of a modulated signal propagating through integrated optic structures like straight waveguides and bends, demonstrating their ability to support wide bandwidths.