title: Reduced propagation loss in silicon strip and slot waveguides coated by atomic layer deposition.
abstract: When silicon strip and slot waveguides are coated with a 50 nm amorphous titanium dioxide (TiO2) film, measured losses at a wavelength of 1.55 μm can be as low as (2 ± 1)dB/cm and (7 ± 2)dB/cm, respectively. We use atomic layer deposition (ALD), estimate the effect of ALD growth on the surface roughness, and discuss the effect on the scattering losses. Because the gap between the rails of a slot waveguide narrows by the TiO2 deposition, the effective slot width can be back-end controlled. This is useful for precise adjustment if the slot is to be filled with, e. g., a nonlinear organic material or with a sensitizer for sensors applications.
authors.affiliation: Department of Micro and Nanosciences, Aalto University School of Electrical Engineering, Aalto, Finland. tapani.alasaarela@aalto.fi
authors.forename: T
authors.initials: T
authors.lastname: Alasaarela
authors.forename: D
authors.initials: D
authors.lastname: Korn
authors.forename: L
authors.initials: L
authors.lastname: Alloatti
authors.forename: A
authors.initials: A
authors.lastname: Säynätjoki
authors.forename: A
authors.initials: A
authors.lastname: Tervonen
authors.forename: R
authors.initials: R
authors.lastname: Palmer
authors.forename: J
authors.initials: J
authors.lastname: Leuthold
authors.forename: W
authors.initials: W
authors.lastname: Freude
authors.forename: S
authors.initials: S
authors.lastname: Honkanen