An electro-optical filter made of a support in which an optical guide with a diffused channel waveguide and of a cover, that are created in borosilicate glass, and which includes a gap obtained by the use of suitable spacers, filled with a grating constituted of alternating strips of polymer and liquid crystal called POLICRYPS (Polymer Liquid CRYstal Polymer Slices), and with first electrodes that are coplanar to the support and next to the optical guide with a channel, that electrically control the grating making the filter tunable, and a manufacturing process.