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VCSEL bandwidth is limited by slow e-h recombination lifetime nanosecond to ∼ 30 GHz (60Gb/s). The transistor laser (TL) has picosecond radiative recombination lifetime; thus, it will have modulation bandwidth higher than VCSELs toward 150 GHz to achieve 300 Gb/s error free transmission and low power operation of energy/bit toward 10 fJ/bit.
Taking a tailings dam in Hebei as the research object, the dynamic response of the dam under action of flood and earthquake is simulated by using a finite element software, and the seismic dynamic response of the dam with respect to acceleration, stress, displacement, liquefaction area and stability are analysed. The results show that, the vertical acceleration increases with the height of the dam,...
Radar must be able to detect targets within the maximum designed range, targets echoes have different power levels due to radar cross section, jamming, and clutter, in this paper a new technique for increasing the wide dynamic range of the radar based on time varying gain amplifier (TVGA) was proposed for achieving compensation of the power loss due to range, and applying an adaptive sweep optimization...
Freezing of Gait (FOG) is a symptom in Parkinson's Disease (PD) patients that negatively impacts their productivity and quality of life. There is a need for external cues to aid PD patients to overcome this freezing phenomenon. Integrating biofeedback with monitoring devices will improve their self-efficacy in going about their daily activities. This paper presents a real-time PD monitoring and biofeedback...
It has been newly found that shorter intervals between program and erase operations can suppress the oxide degradation more significantly in a 0.05 to 5 sec timeframe. Our new analysis clearly demonstrates the following degradation phenomena: a longer interval yields more trapped charges near the Si surface and surface states. Our results also indicate that the oxide degradation occurs more significantly...
Clutter map constant false alarm rate (CFAR) detectors have been utilized in radar systems, which usually uses local threshold estimates from background observations to maintain CFAR level. However, when the local observations contain irrelevant information and/or heavy clutter, its detection performance would be severely degraded. To solve the problem in that clutter-dominated environment, a biparametric...
High Speed Maneuvering Dim Target (HSMDT) detection is the challenging problem in pulsed monostatic airborne radar, especially under jamming and clutter conditions, the problem is not only how to remove clutter and jamming but also when we detect the HSMDT using the airborne radar the range migration and Doppler estimation problems appeared and needed to be compensated. In this paper a new hybrid...
The multi-target location in bistatic MIMO radar under the colored noise is studied in this paper, and a two-stage sparse representation (TSR) method for joint DOD and DOA estimation is proposed. This method obtains the signal subspace by eigenvalue decomposition of the fourth-order cumulants (FOC) matrix. Then, based on the redundant dictionary refined gradually, a sparse linear model is constructed...
Frequency combs, i.e. spectra of equidistant laser lines, are enabling tools in precision spectroscopy and optical frequency metrology [1,2]. Conventionally, frequency combs are generated using mode-locked lasers, where the mode-locking of the optical comb lines implies the generation of a train of ultra-short optical pulses. Frequency combs can link optical frequencies to radio-frequencies (RF) and...
The discovery of passive mode-locking via saturable absorbers [1] has led to optical femto-second pulses with applications ranging from eye-surgery to the analysis of chemical reactions on ultra-short timescales. In the frequency domain a train of such optical pulses corresponds to a frequency comb (equidistant optical laser lines spaced by the pulse repetition rate) [2], which finds use in precision...
The mid-infrared spectral range (λ∼2–20 mm) is of particular importance as many molecules exhibit strong vibrational fingerprints in this region. Optical frequency combs [1, 2] — broadband optical sources consisting of equally spaced and mutually coherent sharp lines — are creating new opportunities for advanced spectroscopy [3, 4, 5]. Here we demonstrate a novel approach to create mid-infrared optical...
We demonstrate soliton mode-locking in continuously pumped, non-linear optical MgF2 microresonators, resulting in low noise frequency comb spectra and ultra-short pulses of 200 fs duration with a repetition rate of 35.2 GHz.
We demonstrate spectral broadening of a low noise microresonator based near-infrared frequency comb to almost two thirds of an octave as required for self-referencing. The low noise properties of the unbroadened spectrum are preserved.
In the presence of arc, partial discharge and thermal discharge, SF6 decomposes into a wide variety of active products which possess different chemical properties. This paper reports on research in SF6 decomposition relating to the ageing- and fault problems of the insulating materials in the gas-insulated equipment. Under the guidance of detection technology, the decomposition mechanism and the decomposed...
Efficient extraction of minimal siphons is fundamentally important in deadlock control. So far, methods that are based on problem reduction and decomposition are recognized as effective ways. In this paper, an improved method is proposed to identify all minimal siphons. New conditions are proposed under which a problem needs not be decomposed. It significantly simplifies the process of problem decomposition...
We present mid-infrared frequency comb generation from crystalline MgF2 microresonators, with mode spacing of 50–150 GHz around the 2.5 μm-wavelength CW-pump. Low phase-noise is verified by beating the comb modes with a narrow linewidth CW laser.
We experimentally investigate the initial dynamics of Kerr-frequency comb formation in crystalline MgF2 and planar Si3N4 microresonator and present a universal, platform independent condition for low phase noise performance.
Mid and near-IR optical frequency combs generation in ultra high Q crystalline and integrated SiN microcavities is presented. Moreover, universal dynamics that influences phase noise is described.
Ultra-high-Q whispering gallery mode (WGM) resonators, with the ability to confine and store optical energy in small volumes enable optical frequency comb generation via four-wave mixing (FWM) [1] as first demonstrated in fused silica microtoroids [2,3]. In contrast to fused silica, resonators made from crystalline materials [4–9] such as CaF2, MgF2 and quartz feature exceptionally low loss over a...
Laser frequency combs [1,2] have become enabling tools for a growing tree of applications, from calibration of astrophysical spectrographs to molecular science. Extension of the frequency comb technology to the mid-infrared “molecular fingerprint” region (2–20 µm) proves crucial for spectroscopy, astronomy and optical diagnosis as most of the strong fundamental molecular vibration frequencies are...
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