title: Submicrometer-wide amorphous and polycrystalline anatase TiO2 waveguides for microphotonic devices.
abstract: We demonstrate amorphous and polycrystalline anatase TiO(2) thin films and submicrometer-wide waveguides with promising optical properties for microphotonic devices. We deposit both amorphous and polycrystalline anatase TiO(2) using reactive sputtering and define waveguides using electron-beam lithography and reactive ion etching. For the amorphous TiO(2), we obtain propagation losses of 0.12 ± 0.02 dB/mm at 633 nm and 0.04 ± 0.01 dB/mm at 1550 nm in thin films and 2.6 ± 0.5 dB/mm at 633 nm and 0.4 ± 0.2 dB/mm at 1550 nm in waveguides. Using single-mode amorphous TiO(2) waveguides, we characterize microphotonic features including microbends and optical couplers. We show transmission of 780-nm light through microbends having radii down to 2 μm and variable signal splitting in microphotonic couplers with coupling lengths of 10 μm.
authors.affiliation: School of Engineering and Applied Sciences, Harvard University, 9 Oxford Street, Cambridge, Massachusetts 02138, USA.
authors.forename: Jonathan D B
authors.initials: JD
authors.lastname: Bradley
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Evans
authors.forename: Jennifer T
authors.initials: JT
authors.lastname: Choy
authors.forename: Orad
authors.initials: O
authors.lastname: Reshef
authors.forename: Parag B
authors.initials: PB
authors.lastname: Deotare
authors.forename: François
authors.initials: F
authors.lastname: Parsy
authors.forename: Katherine C
authors.initials: KC
authors.lastname: Phillips
authors.forename: Marko
authors.initials: M
authors.lastname: Lončar
authors.forename: Eric
authors.initials: E
authors.lastname: Mazur
mesh_terms: D003460:Crystallization / Q000379:methods*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008904:Miniaturization; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology / Q000295:instrumentation*; D017785:Photons; D020349:Surface Plasmon Resonance / Q000295:instrumentation*; D014025:Titanium / Q000737:chemistry*
chemical_list: C009495:titanium dioxide; D014025:Titanium