∇²E + (ω²/c²)n²E = 0
In integrated optics, optical components such as waveguides, couplers, and resonators are designed to interact with each other. The coupling between components is described by the overlap integral of the electric fields.
where E₁ and E₂ are the electric fields of the two components.
The overlap integral is given by:
The scalar wave equation is given by: