A method for fabricating a multi-channel array optical device having uniform spacing between different wavelengths and for having precise wavelengths by accomplishing wavelength adjustment and by the forming of mirror layers simultaneously through a multi-layer binary mask and a selective oxidization process. This method is especially useful for fabricating multi-channel array optical devices including multi-channel passive filters and multi-channel surface emitting laser arrays. The method includes forming a plurality of semiconductor mirror layers on a semiconductor substrate; forming an oxidization protective layer on the plurality of semiconductor mirror layers; selectively removing the oxidization protective layer by using a binary mask to expose the semiconductor mirror layer which will adjust a wavelength; oxidizing the exposed semiconductor mirror layer.