Packaging of micro-lens arrays to photonic integrated circuits using beam shape evaluation

Abstract

We propose a method for aligning and attaching micro-lens arrays to photonic integrated circuits (PICs). Unlike the conventional approach of assessing power coupled to a fiber directly, our method utilizes a beam profiler. This profiler allows us to optimize the lens position by analyzing the transmitted beam shape from the PIC edge coupler through the lens. In conjunction, we employ grating couplers to introduce external light, acting as a ‘beacon’ for optimization. The use of grating couplers enables efficient coupling of external light into the PIC, providing a reference point for alignment. Importantly, our method accommodates both regular waveguide-side-up and upside-down (through-Silicon) orientations of the PIC. This versatility allows us to reproduce coupling results across a 6-channel array, demonstrating robust performance. This innovative approach not only ensures precise alignment and attachment but also opens up new possibilities for photonic packaging. The flexibility to work in different orientations is likely to lead to advancements in the design and assembly of photonic devices.