1993-1995 optical mode solvers

This paper contains a review of recent developments on rigorous methods for deriving normal modes of optical waveguides. These methods can be classified as global methods or resonance methods, depending on whether the unknown is the field upon a surface or along a line. An attempt is made to clarify what can be expected in terms of accuracy for propagation constants and fields; it is suggested that the modal transverse resonance method could be the most accurate of all so far.