Disclosed is a technology related to an optical waveguide which is insensitive to an ambient temperature and is capable of adjusting a wavelength error due to a manufacturing processing deviation. The optical waveguide includes: a clad layer positioned on a substrate; a core layer positioned between the substrate and the clad layer, and including patterns positioned in a first region and a second region; and a wavelength adjusting unit positioned in the first region between the substrate and the clad layer, and configured to adjust a wavelength of an optical signal propagated through patterns passing through the first region based on received electric energy, in which the clad layer includes a material having a Thermo-Optic Coefficient (TOC) with an opposite sign to that of a material included in the core layer.