Optical element for free-space propagation between an optical waveguide and another optical waveguide, component, or device

A method for forming optical elements comprising:

• (i) spatially-selectively processing a first surface of a wafer to define multiple alignment features;
• (ii) spatially-selectively processing the first or a second surface of the wafer to define multiple substantially flat mounting surfaces, the second wafer surface being substantially parallel to the first wafer surface, the multiple mounting surfaces forming an angle with the second wafer surface;
• (iii) forming an optical coating on the first wafer surface or on the second wafer surface;
• and
• (iv) dividing the wafer into individual optical elements, each optical element having a first transmission surface including a portion of the first wafer surface, a second transmission surface including a portion of the second wafer surface, a portion of at least one of the alignment features that forms an element alignment mark, at least one of the substantially flat mounting surfaces arranged between the first and second transmission surfaces, and at least a portion of the optical coating,
• wherein, for each optical element;
• the mounting surface is arranged so that the optical element is self-supporting on a substantially flat mating portion of a waveguide substrate surface;
• and
• the first transmission surface, the second transmission surface, and the mounting surface are arranged so as to position, with the element alignment mark substantially aligned with a corresponding substrate alignment mark on the waveguide substrate, the first and second transmission surfaces at respective orientations relative to the mating portion of the substrate surface, so that an optical beam propagating substantially parallel to the substrate surface and entering the optical element through the first transmission surface propagates as an optical beam through the optical element with the mounting surface between the optical beam and the substrate surface and exits the optical element through the second transmission surface without being internally reflected within the optical element.

A method comprising mounting an optical element on a waveguide substrate having a first optical waveguide formed thereon and at least one substrate alignment mark, the waveguide substrate also having a second optical waveguide formed thereon or a photodetector mounted thereon, wherein;

• the optical element comprises a volume of substantially transparent material having opposing first and second transmission surfaces, a substantially flat mounting surface arranged between the transmission surfaces, at least one element alignment mark, and an optical coating on the first transmission surface;
• the optical element is mounted on the waveguide substrate with the mounting surface on a substantially flat mating portion of the substrate surface, the mounting surface being arranged so that the optical element is self-supporting on the substrate surface;
• the optical element is arranged and positioned, with the element alignment mark substantially aligned with the substrate alignment mark, so as to position the first and second transmission surfaces at respective orientations relative to the substrate surface and to the waveguide so that a portion of an optical signal emerging as an optical beam from an end face of the first optical waveguide enters the optical element through the first transmission surface, propagates as an optical beam through the optical element with the mounting surface between the optical beam and the substrate surface, and exits the optical element as an optical beam through the second transmission surface without being internally reflected within the optical element;
• and
• the photodetector or the second optical waveguide is positioned so as to receive directly the portion of the optical signal propagating as the optical beam exiting the optical element through the second transmission surface.