  This paper proposes an efficient boundary-integral based "windowed Green
function" methodology (WGF) for the numerical solution of three-dimensional
electromagnetic problems containing dielectric waveguides. The approach, which
generalizes a two-dimensional version of the method introduced recently,
provides a highly effective solver for general electromagnetic problems
containing waveguides. In particular, using an auxiliary integral
representation, the proposed method is able to accurately model incident mode
excitation. On the basis of a smooth window function, the integral operators
along the infinite waveguide boundaries are smoothly truncated, resulting in
errors that decay faster than any negative power of the window size.
