Optical waveguides fabricated in atomic layer deposited Al2O3 by ultrafast laser ablation

Abstract We report on the fabrication of optical waveguides by ultrafast laser ablation of Al2O3. First, a thin film was grown by atomic layer deposition (ALD) on fused silica substrate, followed by laser ablation micromachining the surface material in order to produce a rib waveguide. A multimode behavior of the waveguide and propagation loss of 3.8 dB/cm was measured at 632.8 nm. Microstructural characterization showed that roughness is the major issue to overcome the propagation losses. Results obtained in this work suggest a viable methodology for the fabrication of optical waveguides for potential applications in integrated photonics.