Femtosecond laser fabrication of a monolithic coupled waveguide-lens system in bulk fused silica

We have developed a novel method to couple free-space light into a waveguide using laser-based micro-processing techniques. The resulting system is entirely monolithic. The coupling lens and waveguide are fabricated from the same material (fused silica) ensuring that no free-space alignment is required. The waveguide is written via femtosecond-laser writing and the coupling lens is written using a laser ablation and reflow process. Markers are used to ensure alignment between the two components during fabrication process. This approach opens up opportunities to deploy integrated optical systems in harsh environments with tolerance to mechanical shock.