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The impact of electrode configurations, materials, thicknesses and interdigital transducer (IDT) duty factor (DF) on performance of aluminum nitride (AlN) Lamb wave resonators is analyzed and summarized for the first time in this study. By careful design and selection of the transducer and bottom electrodes, the effective electromechanical coupling coefficient (k2eff) of the AlN Lamb wave resonator...
We report on characterization of microsale lead zirconate titanate (PZT) thin film cantilevers, by both optical and electrical measurements, for up to the 7th resonance mode in 2kHz to 2MHz frequency range, with quality (Q) factors between 380 and 600. We also calibrate the PZT thin film's inverse piezoelectric coefficient (e31 ≈ −5C/m2). This work presents a multiphysical characterization of important...
We evaluate the stability of two-way time and frequency transfer over a 50 km fiber optic link established using a commercially available fiber optic modem. For this evaluation we report the residual phase noise, total Allan deviation, total time deviation, and temperature fluctuations of the optical time and frequency transfer network. This two-way transfer is transmitted over an underground, dark...
The ultracold atoms served as quantum references is a key part of optical lattice clocks, and the thermal dynamics of the atoms in the optical lattice affects the uncertainty and stability of the lattice clocks. Since the carrier spectrum of clock transition in lattices reflects the thermal dynamics of cold atoms, we can obtain the temperature of atoms by measuring the carrier spectrum in 171Yb optical...
This work presents the design and characterization for composite Aluminum Nitride on Silicon based thin Film Bulk Acoustic Wave Resonators (c-FBAR) fabricated using a proprietary InvenSense AlN-MEMS + CMOS process. High performance pentagon shaped resonators are fabricated and operated under a high-order thickness-extensional mode with an electromechanical coupling coefficient of 2.21% and an unloaded...
The uncertainty of measurements in timing systems is a function not only of the quality of the instruments and system components (time interval counters, pulse distribution amplifiers, Global Navigation Satellite System (GNSS) receivers, etc.) but also of the quality of the pulses carrying the timing information. This paper presents a study of the consequences of using pulse-per-second (PPS) signals...
This paper presents an AO spurious mode mitigation technique for Aluminum Nitride (AlN) laterally vibrating resonators (LVRs). The technique attaches two identical SiO2 addendums to the lateral edges of the suspended AlN resonator body to shift the asymmetrical (AO) spurious modes away from the intended SO mode vibration. The AlN resonators with SiO2 addendums have been investigated theoretically...
This paper presents MEMS resonant stress sensors for real-time monitoring of induced shear stress during formation of a thin film on a micro-diaphragm. The device is comprised of a thin silicon membrane coupled to a thermal-piezoresistive resonator. Membrane deflection due to the stress resulting from deposition or growth of a thin film deforms the resonator, thus changing its resonance frequency...
Generation and distribution of very low phase noise and spurious-free microwave Local Oscillator (LO) is needed for most of the radar or electronic warfare applications. Microwave optical technologies are well dedicated to this purpose. In a previous paper, we have studied a directly-modulated optical link. Thanks to new experimentations with external-modulated optical links, we compare those two...
Phononic crystal (PnC) in half-space allows anisotropic propagation and band gaps for surface acoustic wave (SAW) and promise applications such as filters and reflectors. For the feasible MEMS fabrication, a PnC comprised of cylindrical holes in a SiO2 layer covering a 128°rotated Y-cut LiNbO3 substrate was applied and the acoustic modes were analyzed numerically. The band gap for SAW was indicated...
Honeywell is developing a cold atom primary standard with reduced size, weight and power in comparison to existing clocks with similar performance, showing the feasibility of achieving the long-term goal of near-GPS-quality performance in a miniaturized, fieldable package. While the physics of these clocks is well known, unique challenges with miniaturizing the components and subsystems have required...
Optical frequency division based on mode-locked laser frequency combs makes possible the coherent transfer of frequency stability from optical systems to electronics. It has enabled a revolution in time keeping and frequency metrology. In this paper we describe progress on new methods for frequency comb generation including whispering-gallery-based microcombs and electro-optical comb generation. Demonstration...
The Ω preprocessing was introduced to improve phase noise rejection by using a least square algorithm. The associated variance is the PVAR which is more efficient than MVAR to separate the different noise types. However, unlike AVAR and MVAR, the decimation of PVAR estimates for multi-τ analysis is not possible if each counter measurement is a single scalar. This paper gives a decimation rule based...
This paper presents an overview of Lead-Zirconate-Titanate (PZT) and PZT-on-silicon MEMS resonator and filter technology at HF and low-VHF frequencies; highlighting the capability for bandwidth tuning, high coupling, high Q, and low-loss filter performance without external impedance matching.
This paper investigates and compares three methods for the analysis of the thin film bulk acoustic resonator (FBAR) in order to study the propagation of plate waves in the device. The finite element method (FEM) is compared to the Transfer Matrix (TM) and Global Matrix (GM) techniques, which are carefully modified in order to take into account the mixed-multilayer structure of the resonator. To the...
We demonstrate that the use of thick AlN films in Very-High-Frequency (VHF) contour-mode resonators (CMRs) enables a reduction of thermoelastic damping (TED) occurring in the metallic layers sandwiching the AlN film. This technique leads to a large improvement of the device quality factor (Q increase >72%) with respect to thin-film counterparts, resulting into the highest Q ever measured in air...
We demonstrate the first ladder filter based on the use of the recently demonstrated cross-sectional Lamé mode resonators (CLMRs). This device shows a fractional bandwidth (BW3db) as high as 3.3% while enabling an insertion-loss as low as 2.5 dB. As the resonance frequency of CLMRs can be controlled lithographically without significantly degrading their electromechanical coupling coefficient (kt2),...
This work reports an ultra-low-power temperature-compensated CMOS-MEMS oscillator based on an uniform temperature design that ensures low temperature gradient of the proposed resonator to attain high frequency stability. The oven heating efficiency greater than 140°C/mW is achieved in this work by a proper thermal isolation design. In addition, the lowest temperature coefficient of frequency (TCf)...
In this paper, we present new results on the development of an original acoustic waveguides concept based on a Periodically Poled Lithium Niobate transducer. Periodically poled transducers have been investigated recently as an alternative to classical inter-digital transducers for the excitation and detection of guided acoustic waves. We expose here two different structures of RF resonators based...
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