Low-loss titanium dioxide waveguides and resonators using a dielectric lift-off fabrication process

Abstract

We present a bi-layer lift-off fabrication approach to create low-loss amorphous titanium dioxide (TiO2) integrated optical waveguides and resonators for visible and near-infrared applications. This approach achieves single-mode waveguide losses as low as 7.5 dB/cm around 633 nm and 1.2 dB/cm around 1550 nm, a factor of 4 improvement over previous reports, without the need to optimize etching conditions. Depositing a secondary 260-nm TiO2 layer can reduce losses further, with the optimized process yielding micro-ring resonators with loaded quality factors as high as 1.5 × 10(5) around 1550 nm and 1.6×10(5) around 780 nm. These losses render our TiO2 devices suitable for visible and telecommunications applications; in addition, the simplicity of this lift-off approach is broadly applicable to other novel material platforms, particularly using near-visible wavelengths.

Octave Spanning Supercontinuum in Titanium Dioxide Waveguides

“…As a consequence, we believe that for the present experiment, the finite length of the device is not the main limiting effect. Note that a different process of fabrication avoiding etching could decrease drastically such losses down to around 1 dB/cm [44]. Once the input conditions are properly adjusted, the output camera is replaced by a second single-mode lensed fibre connected to an optical spectrum analyser (OSA) operating in the near-infrared range (Anritsu MS9740A).…”

Double metal layer lift-off process for the robust fabrication of plasmonic nano-antenna arrays on dielectric substrates using e-beam lithography

“…Given the subwavelength dimensions of plasmonic nano-antennas and considering the inverse relationship between the Raman scattering cross-section and wavelength used, 785 nm is one the most used wavelengths to perform this technique since it offers a compromise between performance and technological requirements. Integrated optical waveguides operating at this wavelength are often fabricated using dielectric materials, including silicon dioxide (SiO 2 ), silicon nitride (Si 3 N 4 ) [13], aluminum oxide (Al 2 O 3 ) [14,15] and titanium oxide (TiO 2 ) [16].…”

Demonstration of High-Speed Optical Transmission at 2 µm in Titanium Dioxide Waveguides

“…Note also that it exhibits a higher linear refractive index, which is critical for a stronger confinement [19]. Up to now, detailed studies have taken advantage of its negative thermo-optic coefficient [18,20] and its transparency in the visible range [21,22], or have reported on its linear and nonlinear properties in the C-band [19,23,24]. In this work, we experimentally explore, for the first time, TiO 2 as an efficient medium for a photonic component operating at 2 µm.…”