Scalable fabrication of aligned micro-optics enabled by two-photon grayscale lithography

We showcase two-photon grayscale lithography (2GL) with in-situ alignment as the next step towards scalable fabrication of micro-optics. While the laser-based direct write technology is known to create true 3D structures with sub-micron resolution, the use of Grayscale Lithography (2GL®) enables high-speed of the fabrication with surface roughness below 5nm and shape accuracy down to below 200nm. We demonstrate user friendly 3D detection algorithms in our nanoPrintX software for automatic alignment towards a variety of topographies and material platforms with very high accuracy better than 100 nm. The versatility of our approach is shown via micro-optical elements aligned to fiber tips, photonic edge couplers, and photonic grating couplers for improved coupling losses and beam quality. We demonstrate the automatic fabrication of 480 on-chip optical coupling elements on a photonic integrated circuit with excellent optical surface qualities and highly reproducible placement accuracy.