A method for manufacturing an optical device including at least one silicone elastomer optical waveguide includes the steps of providing a substantially rigid mold with a patterned surface, providing a core layer of a curable silicone elastomer, patterning the core layer by means of the patterned surface of the substantially rigid mold, curing the patterned core layer, and removing the substantially rigid mold from the patterned core layer. The method advantageously allows the manufacture of an optical device including at least one optical waveguide in a single step and in a reproducible manner.