A Tellurium Oxide Microcavity Resonator Sensor Integrated On-Chip with a Silicon Waveguide

We report on thermal and evanescent field sensing from a tellurium oxide optical microcavity resonator on a silicon photonics platform. The on-chip resonator structure is fabricated using silicon-photonics-compatible processing steps and consists of a silicon-on-insulator waveguide next to a circular trench that is coated in a tellurium oxide film. We characterize the device’s sensitivity by both changing the temperature and coating water over the chip and measuring the corresponding shift in the cavity resonance wavelength for different tellurium oxide film thicknesses. We obtain a thermal sensitivity of up to 47 pm/°C and a limit of detection of 2.2 × 10−3 RIU for a device with an evanescent field sensitivity of 10.6 nm/RIU. These results demonstrate a promising approach to integrating tellurium oxide and other novel microcavity materials into silicon microphotonic circuits for new sensing applications

High-<i>Q</i> TeO₂–Si Hybrid Microring Resonators

We present the design and experimental measurement of tellurium oxide-clad silicon microring resonators with internal Q factors of up to 1.5 × 106, corresponding to a propagation loss of 0.42 dB/cm at wavelengths around 1550 nm. This compares to a propagation loss of 3.4 dB/cm for unclad waveguides and 0.97 dB/cm for waveguides clad with SiO2. We compared our experimental results with the Payne–Lacey model describing propagation dominated by sidewall scattering. We conclude that the relative increase in the refractive index of TeO2 reduces scattering sufficiently to account for the low propagation loss. These results, in combination with the promising optical properties of TeO2, provide a further step towards realizing compact, monolithic, and low-loss passive, nonlinear, and rare-earth-doped active integrated photonic devices on a silicon photonic platform

Low-Temperature and Low-Pressure Silicon Nitride Deposition by ECR-PECVD for Optical Waveguides

We report on low-temperature and low-pressure deposition conditions of 140 °C and 1.5 mTorr, respectively, to achieve high-optical quality silicon nitride thin films. We deposit the silicon nitride films using an electron cyclotron resonance plasma-enhanced chemical vapour deposition (ECR-PECVD) chamber with Ar-diluted SiH4, and N2 gas. Variable-angle spectroscopic ellipsometry was used to determine the thickness and refractive index of the silicon nitride films, which ranged from 300 to 650 nm and 1.8 to 2.1 at 638 nm, respectively. We used Rutherford backscattering spectrometry to determine the chemical composition of the films, including oxygen contamination, and elastic recoil detection to characterize the removal of hydrogen after annealing. The as-deposited films are found to have variable relative silicon and nitrogen compositions with significant oxygen content and hydrogen incorporation of 10–20 and 17–21%, respectively. Atomic force microscopy measurements show a decrease in root mean square roughness after annealing for a variety of films. Prism coupling measurements show losses as low as 1.3, 0.3 and 1.5 ± 0.1 dB/cm at 638, 980 and 1550 nm, respectively, without the need for post-process annealing. Based on this study, we find that the as-deposited ECR-PECVD SiOxNy:Hz films have a suitable thickness, refractive index and optical loss for their use in visible and near-infrared integrated photonic devices

Low-Temperature and Low-Pressure Silicon Nitride Deposition by ECR-PECVD for Optical Waveguides

We report on low-temperature and low-pressure deposition conditions of 140 °C and 1.5 mTorr, respectively, to achieve high-optical quality silicon nitride thin films. We deposit the silicon nitride films using an electron cyclotron resonance plasma-enhanced chemical vapour deposition (ECR-PECVD) chamber with Ar-diluted SiH4, and N2 gas. Variable-angle spectroscopic ellipsometry was used to determine the thickness and refractive index of the silicon nitride films, which ranged from 300 to 650 nm and 1.8 to 2.1 at 638 nm, respectively. We used Rutherford backscattering spectrometry to determine the chemical composition of the films, including oxygen contamination, and elastic recoil detection to characterize the removal of hydrogen after annealing. The as-deposited films are found to have variable relative silicon and nitrogen compositions with significant oxygen content and hydrogen incorporation of 10–20 and 17–21%, respectively. Atomic force microscopy measurements show a decrease in root mean square roughness after annealing for a variety of films. Prism coupling measurements show losses as low as 1.3, 0.3 and 1.5 ± 0.1 dB/cm at 638, 980 and 1550 nm, respectively, without the need for post-process annealing. Based on this study, we find that the as-deposited ECR-PECVD SiOxNy:Hz films have a suitable thickness, refractive index and optical loss for their use in visible and near-infrared integrated photonic devices

Progress on a hybrid tellurite glass and silicon nitride waveguide platform for passive, active, and nonlinear photonic integrated circuits

We present on recent progress on a hybrid tellurite glass and silicon nitride photonic platform. We show low loss waveguides and Q factors < 10^6 in microring resonators. We also show rare-earth-doped active devices, including erbium-doped and thulium-doped waveguide amplifiers and thulium-doped microring lasers. Using the same approach, we demonstrate nonlinear functionalities including efficient four-wave-mixing, supercontinuum generation and third harmonic generation in compact microring resonators and waveguides. The platform is highly promising for compact and low-cost passive, active and nonlinear photonic integrated circuits for applications in computing, communications, sensing and metrolog