Effective use of diffraction gratings in optical devices based on diffused waveguides

Numerical examples are used to discuss ways of increasing the efficiency of mode diffraction by corrugated parts of diffused waveguides. It is shown that the use of dielectric coating films may provide a way of enhancing the mode diffraction by a corrugation. The WKB approximation is used to estimate the required thickness of the coating film. A comparison is made of the methods for enhancement of the diffraction of modes in diffused waveguides by metallization of corrugations and by dielectric coating.