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Soliton microcombs are demonstrated at both 1064 nm and 778 nm by dispersion-engineering on-chip silica resonators. These are the shortest wavelength soliton microcombs demonstrated to date and have potential applications in optical clocks and metrology.
A low-frequency electrical spectrum analysis method is researched for evaluating broadband characteristics of high-speed dual-parallel Mach-Zehnder modulators (DPMZMs) based on dual-frequency modulation and fixed-frequency bias. The method enables the broadband and high-resolution evaluation for the modulation depth and half-wave voltage of a high-speed DPMZM by using a low-frequency photodetector...
InAs/InGaAs quantum dot mode-locked lasers are fabricated and characterized. The modal gain as the saturable absorber voltage (SAV) changes is investigated. The ground state lasing dominates at low SAV, and excited state transition emerges when SAV increases.
The ideality factor of a 2 μm InGaSb/AlGaAsSb quantum well laser is investigated. The total ideality factor comes mainly from the central p-n junction and two metal-semiconductor junctions. It decreases from 4.0 to 3.3 when the temperature is increased from 20 to 80 oC.
An on-wafer and self-calibrated scheme is proposed and demonstrated for self-referenced microwave characterization of a silicon integrated optical transceiver. The proposed self-calibration method enables on-wafer selective extraction of microwave characteristic parameters of high-speed modulators and photodiodes in the integrated optical transceiver, without the need for extra electrical-to-optical...
Chiral metamirrors can reflect one circularly polarized light without changing its handedness, while almost completely absorb the other, which would have many potential applications in engineering. In this paper, recent progresses of our group on the chiral metamirrors are reviewed. Firstly, we discuss the general method to design the chiral metamirrors under the framework of Jones calculus. The structural...
RAL Space and its project partner PRG are tasked with providing space-qualified heterodyne receiver front-ends operating between 165.5 GHz and 325 GHz for the Microwave Sounder (MWS), the Microwave Imager (MWI) and the Ice Cloud Imager (ICI) of the MetOp Second Generation (MetOp-SG) series of satellites. The preliminary design of the receiver front-ends is now complete. Extensive tests on performance...
A limiting factor of GaAs Schottky diodes used as mixers in heterodyne receivers is their high intrinsic noise when compared to SIS or HEB devices. This work presents results on the numerical optimization of fundamental Schottky diode mixers, results which predict a significant improvement in the noise performance of current Schottky mixer technology in the THz band. The optimization of the Schottky...
A Multi-band Body Wearable Antenna (MBWA) has been designed to cover six communications bands: SINCGARS band (30 MHz-88 MHz), Air & Marine band (116 MHz–174 MHz), UHF band (225 MHz–450 MHz), UHF-Public Safety band (450 MHz-512 MHz), UHF SATCOM band (225 MHz-318 MHz) and Soldier Radio Waveform (1–2 GHz). The MBWA can also be remoted from the radio and the soldier to enhance communications range...
Millimeter wave (mmWave) phased arrays have been demonstrated recently as the technology that enables 5G mobile's grand vision of high data rate and low latency, as well as provides a physical layer security stemming from mmWave's high propagation loss in the air interface. This paper explores the fundamental issues in both capacity and security/privacy of 5G wireless, and proposes a solution to enhance...
The bandgap reference circuits are very sensitive to electromagnetic interferences (EMI) which induce voltage offset on their outputs. Two bandgap chips with different technologies are designed for EMC study. The conducted immunity of VDD and VSS pins are tested following direct power injection (DPI) method. The aim of this study is to compare the susceptibility characteristics of same bandgap circuit...
This paper presents a practical model predictive attitude control method for aerodynamic flight vehicles with wide envelope and independent of angular velocity measurements. At first, the original nonlinear longitudinal dynamics is compensated by an extended state observer, and the compensated system can be approximated by a second-order integrator. Then a modified generalized predictive control algorithm...
Ge n- and p-FinFETs with different interfacial layer ferroelectric HfZrOx (IL-FE-HZO) gate stacks have been demonstrated systematically by various annealing conditions for the first time. Microwave annealing (MWA) not only shows enhanced FE characteristics but also suppresses the gate leakage and Ge interdiffusion compared with conventional rapid thermal annealing (RTA). While HZO on Al2O3 IL results...
Three-dimensional (3D) fanout package stacking offers new levels of performance, high-density integration, and form factor advantages. Known-good fanout packages are stacked, and the vertical connection is built through Cu pillars in the molding area and solder bumps. Compared to existing TSV-based 3D integrated circuits (3DIC) technology, this solution reduces thermal crosstalk when integrating devices...
Three-dimensional (3D) fanout package stacking offers new levels of performance, high-density integration, and form factor advantages. Known-good fanout packages are stacked, and the vertical connection is built through Cu pillars in the molding area and solder bumps. Compared to existing TSV-based 3D integrated circuits (3DIC) technology, this solution reduces thermal crosstalk when integrating devices...
The effect of external stress on split mode gyroscope bias is identified by experimental approaches for the first time in this paper. A long-term drift relates to installation mode but independent of temperature variation is observed and its origination is explored. Two bias alteration mechanisms are validated, namely, variations of quadrature coupling and in-phase leakage from drive axis. Both of...
A novel MEMS inertial switch with electrostatic force assistance and multi-step pull-in behavior has been designed, which can help the electrodes weaken the bounce and keep a long contact in the inertial switch before the leakage of electricity ends compared with the traditional rigid contact between electrodes. The dynamic switching and pull-in performance is simulated by finite element method. The...
A novel piezoelectric bridge transducer was developed for an energy harvesting application from vehicle induced loading on pavement. A unique electrode design enables the PZT to be poled horizontally, enabling the d33 piezoelectric coefficient to be utilized by the transducer, enhancing energy output. The transducers were fabricated and assembled in an energy harvesting module and the output energy...
A nonvolatile resistance effect modulated by pulse with laser was observed in nano-carbon oxide semiconductor structures. By applying a short voltage pulse with laser illumination, the lateral resistance of the structure can be permanently changed. The resistance change ratio can reach up to 65%. More interestingly, the effect shows polarity under different illumination spot and voltage directions...
Vernier Permanent-magnet machine (VPMM) has been recognized in recent years as a substitute for permanent magnet synchronous machines (PMSM) in direct-drive applications such as wind turbine generators, motorcycles and electric vehicle/hybrid electric vehicle (EV/HEV) [1].
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