OPTICAL ASSEMBLY WITH DIFFRACTIVE OPTICAL ELEMENT

An optical assembly comprising: (a) a crystalline substrate having a top planar surface and a crystalline plane angle; (b) at least one groove defined in the top planar surface and having side walls extending from an edge of the substrate to a terminal end, the groove having a first facet at the terminal, the first facet having a first angle relative to the top planar surface, the first facet being reflective; (c) an optical conduit having an optical axis and an end face optically coupled with the first facet; (d) a waveguide; and (e) a diffractive optical element (DOE) disposed above the first facet and configured to couple light between the waveguide and the optical conduit as reflected by the first facet.