The invention provides a process of manufacturing an optical waveguide for optically connecting a plurality of optical devices, comprising the steps of: disposing a resin composition between two or more optical devices, the resin composition comprising a resin and a 1,4-dihydropyridine derivative, forming an optical path through the resin composition between the optical devices by light having a wavelength capable of inducing a structural change in the 1,4-dihydropyridine derivative, and removing the 1,4-dihydropyridine derivative from the resulting resin composition. Also disclosed is a connection structure obtained by the process.