Fabrication of submicrometer high refractive index tantalum pentoxide waveguides for optical propulsion of microparticles

Design, fabrication, and optimization of tantalum pentoxide (Ta2O5) waveguides to obtain low-loss guidance at a wavelength of 1070 nm are reported. The high-refractive index contrast (Δn ~ 0.65, compared to silicon oxide) of Ta2O5 allows strong confinement of light in waveguides of submicrometer thickness (200 nm), with enhanced intensity in the evanescent field. We have employed the strong evanescent field from the waveguide to propel micro-particles with higher velocity than previously reported. An optical propelling velocity of 50 µm/s was obtained for 8 µm polystyrene particles with guided power of only 20 mW

Waveguiding and photoluminescence in Er³⁺-doped Ta₂O₅ planar waveguides

The optimization of erbium-doped Ta2O5 thin film waveguides deposited by magnetron sputtering onto thermally oxidized silicon wafer is described. Optical constants of the film were determined by ellipsometry. For the slab waveguides, background losses below 0.4dB/cm at 633nm have been obtained before post-annealing. The samples, when pumped at 980nm yielded abroad photoluminescence spectrum (FWHM ~50 nm) centred at 1534nm, corresponding to 4 I 13/2 to the 4 I 15/2 transition of Er3+ ion. The samples were annealed up to 600 °C and both photoluminescence power and fluorescence lifetime increase with post-annealing temperature and a fluorescence lifetime of 2.4ms was achieved, yielding promising results for compact waveguide amplifier

Sub-micron period relief grating structures inscribed on Erbium doped Ta₂O₅ waveguides using 213 nm, 150 ps laser radiation

Tantalum Pentoxide (Ta2O5) films exhibit high refractive index (2.1 @ 1550 nm), transparency between 300 nm and 2000 nm wavelengths, compatibility with silicon processing techniques and high photosensitivity [1], making them ideal for realising compact multifunctional planar lightwave circuits (PLCs)

Spectroscopy, modeling, and performance of Erbium-Doped Ta₂O₅ waveguide amplifiers

The design, fabrication, spectroscopic characterization, and performance of an Er:Ta2O5 rib waveguide amplifier is described. Rib waveguides with low loss (< 0.65 dB/cm at 1600 nm) were obtained. Their absorption spectrum was measured and McCumber theory was employed to obtain the emission spectrum, leading to the absorption and emission cross sections. Numerical modeling for gain optimization in Er:Ta2O5 waveguide amplifiers is presented, employing the experimentally determined parameters. Finally, net optical gain of 2.1 dB/cm at 1531.5 nm is demonstrated in a 2.3 cm long Er:Ta2O5 rib waveguide when pumped with 977 nm laser diode, and compared with simulations to deduce the extent of upconversion

High index contrast Er:Ta₂O₅ waveguide amplifier on oxidised silicon

We report a high index contrast erbium doped tantalum pentoxide waveguide amplifier. 2.3 cm long waveguides with erbium concentration of 2.7 × 1020 cm-3 were fabricated by magnetron sputtering of Er-doped tantalum pentoxide on oxidised silicon substrates and Ar-ion milling with photolithographically defined mask. A net on-chip optical gain of ~2.25 dB/cm at 1531.5 nm was achieved with 20mW of pump power at 977 nm launched into the waveguide. The pump threshold for transparency was 4.5mW.<br/