Systems and methods for passively-aligned optical waveguide edge-coupling

A method for edge-coupling of electro-optic chips, comprising:

• forming a facet at an edge of a first chip so that a first plurality of optical waveguides is exposed at the facet of the first chip;
• forming a first lateral alignment trench within the first chip on a first side of the first plurality of optical waveguides;
• forming a second lateral alignment trench within the first chip on a second side of the first plurality of optical waveguides;
• forming a facet at an edge of a second chip so that a second plurality of optical waveguides is exposed at the facet of the second chip, wherein the facet of the second chip is formed so that the second chip includes a first lateral alignment feature located on a first side of the second plurality of optical waveguides and a second lateral alignment feature located on a second side of the second plurality of optical waveguides, wherein the first lateral alignment feature is formed to fit into the first lateral alignment trench of the first chip and the second lateral alignment feature is formed to fit into the second lateral alignment trench of the first chip, wherein the facet of the second chip is also formed to extend a specified distance into the second chip so that a portion of the second chip extends from the facet of the second chip over at least a portion of the first chip when the second chip is positioned against the first chip, wherein the specified distance is defined to achieve vertical alignment of the second plurality of optical waveguides with the first plurality of optical waveguides;
• and
• positioning the second chip against the first chip so that the facet of the second chip contacts the facet of the first chip and so that the second plurality of optical waveguides respectively align with the first plurality of optical waveguides.