An optical waveguide and method of providing that enhances high-speed communication includes a waveguide medium having at least one groove, in which a side wall exposed by the groove is formed inclined with respect to the traveling path of light. A reflection block having a reflection mirror faces the inclined side wall of the groove, in which the reflection block is typically arranged in the groove to face the side wall of the groove, and a refractive index matching layer is typically a coating arranged between the side wall of the groove and the reflection mirror.