Low Loss, Asymmetric Aperture-Matched Microlens Arrays

Photonic imaging devices (PIDs) face challenges in efficiently coupling light into and out of photonic integrated circuits (PICs). Current microlens processes lack the necessary control over surface shape and quality to achieve aberration reduction, optimal mode shaping, and the axis-dependent numeric apertures (NA) required for efficient coupling to gratings. Flexible inkjet printing of volumetric gradient index (GRIN) micro-optical elements offers a promising solution. These elements can be fabricated with complex freeform index profile that can tailor the spot size for enhanced coupling.Ā To demonstrate these benefits, a design of experiments (DOE) will identify index distributions and process parameters for optimal micro-optical element performance in a test array comprised of various types of microlenses. An application-specific microlens array (MLA) will be developed to demonstrate optimized coupling into and out of waveguide grating couplers that matches modeling and simulation (M&S) results.Ā To assess variability, multiple test array lots will be fabricated under statistical process control (SPC) using volume production equipment. Government-received MLAs will undergo characterization and validation, and additional MLAs will undergo environmental and reliability testing.