Analysis and evaluation of various optical waveguide grating couplers for integrated optics

Abstract

The photonic integrated circuits can be designed by analyzing optical waveguide structures with different types of gratings. The periodic coupling is analyzed for these waveguide structures using coupled mode theory, for both phase matched and non-phase matched conditions. The variations of coupling lengths based on refractive indices differences, operating wavelengths and separation between waveguides are analyzed and obtained the results. The difficulties of integrating the available optical components, which are in all fiber form, in photonic integrated circuits are conquered by these couplers. Integrated optics provides a solution to integrating these components on a single substrate, which miniaturizes the component. By analyzing different waveguide structures, components like optical couplers, wavelength filters, power dividers, polarization transformers etc. can be designed. This paper proposes rectangular, triangular and sinusoidal ridge waveguide structures that act as optical couplers, which provide better coupling efficiency.