Alasaarela T, Korn D, Alloatti L, Säynätjoki A, Tervonen A, Palmer R, Leuthold J, Freude W, Honkanen S. Reduced propagation loss in silicon strip and slot waveguides coated by atomic layer deposition.
Opt Express 2011;
19:11529-11538. [PMID:
21716384 DOI:
10.1364/oe.19.011529]
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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.
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