Tens of GHz Tantalum pentoxide‐based micro‐ring all‐optical modulator for Si photonics

Abstract

A tantalum pentoxide-based (Ta 2 O 5 -based) micro-ring alloptical modulator was fabricated. The refractive index inside the micro-ring cavity was modified using the Kerr effect by injecting a pumped pulse. The transmittance of the ring resonator was controlled to achieve all-optical modulation at the wavelength of the injected probe. When 12 GHz pulses with a peak power of 1.2 W were coupled in the ring cavity, the transmission spectrum of the Ta 2 O 5 resonator was redshifted by 0.04 nm because of the Kerr effect. The relationship between the modulation depth and gap of the Ta 2 O 5 directional coupler is discussed. An optimized gap of 1100 nm was obtained, and a maximum buildup factor of 11.7 with 84% modulation depth was achieved. The nonlinear refractive index of Ta 2 O 5 at 1.55 μm was estimated as 3.4 × 10 −14 cm 2 /W based on the Kerr effect, which is almost an order of magnitude higher than that of Si 3 N 4 . All results indicate that Ta 2 O 5 has potential for use in nonlinear waveguide applications with modulation speeds as high as tens of GHz.

Ab Initio Simulation of Ta2O5: A High Symmetry Ground State Phase with Application to Interface Calculation

“…Tantalum pentoxide (Ta 2 O 5 ) is a versatile functional dielectric that can be used as electrolytic capacitor, optical modulator, optical coating, high‐K gate dielectric material in microelectronics, and the switching layer in memristors . Despite its wide range of applications, the knowledge of its exact structure is nevertheless still limited.…”

Ultra-low-loss Ta_2O_5-core/SiO_2-clad planar waveguides on Si substrates

“…Due to the material's extremely large bandgap value (3.8 eV), two-photon absorption (TPA) and TPA-induced free-carrier absorption are of little to no concern when operating Ta 2 O 5 -based devices at high powers [17][18][19]. These important material parameters when considering waveguide design optimizations are summarized below in Table 1.…”

Tantala Kerr nonlinear integrated photonics

“…Tantala deposited by ion-beam sputtering (IBS) has long been used in lowloss, high-reflectivity mirror coatings for various fundamental experiments [23]. Over the past four decades at least, tantala has attracted great attention as a photonic material due to its high refractive index, large bandgap, low stress, low optical loss, low thermo-optic (TO) coefficient, and factor of three higher nonlinearity than SiN [24,25]; the majority of tantala's properties [26][27][28][29][30] are comparable or superior to SiN. Recently, IBS-deposited tantala has been used for photonic waveguide fabrication [27] due to its high transparency.…”

“…In low-confinement tantala-core waveguides, an ultralow loss of 3 dB/m has been reported [27]. However, high-confinement resonators have only been explored with RF sputtered tantala, and only relatively low quality factor ( 𝑄 ) has been reported [24]. Four-wave mixing experiments with high-confinement tantala waveguides and relatively low optical loss (1.5 dB/cm) have been reported [24,31,32].…”