Search results for "Q factor"
showing 10 items of 35 documents
PhoXonic Whispering Gallery Mode Resonators: parametrical optomechanic oscillations and its applications
2021
We report on the experimental analysis of parametrical optomechanical oscillations and photo-acoustical applications such as flow cytometers in hollow phoxonic whispering gallery mode resonators. Both phenomena can be enchanced or suppressed and showed chaotic behavior.
To the theory of high-power gyrotrons with uptapered resonators
2010
In high-power gyrotrons it is desirable to combine an optimal resonator length with the optimal value of the resonator quality factor. In resonators with the constant radius of the central part, the possibilities of this combination are limited because the quality factor of the resonator sharply increases with its length. Therefore the attempts to increase the length for maximizing the efficiency leads to such increase in the quality factor which makes the optimal current too small. Resonators with slightly uptapered profiles offer more flexibility in this regard. In such resonators, one can separate optimization of the interaction length from optimization of the quality factor because the …
Limits of terrestrial optical fiber systems for ultra-high bit rate RZ data transmissions (from 160 Gbit/s to 1.28 Tbit/s)
2007
This article numerically investigates the fundamental limits of the terrestrial RZ data transmission systems based on SMF/DCF dispersion map for bit rates ranging from 160 Gbit/s to 1.28 Tbit/s. The system includes an erbium doped fiber amplifier and pre-and post-compensation stages. After filtering and detection, the system performance is characterized using the usual Q-factor.
Suppression of soliton self-frequency shift by up-shifted filtering
2002
We propose an efficient method for suppressing the soliton self-frequency shift in high-speed transmission lines by means of up-shifted filters.
Extracting parameters from semi-log plots of polycrystalline silicon PV modules outdoor I–V data: Double-exponential model revisited
2010
This paper presents a method for extracting physically meaningful parameters from measured I–V curves of PV modules. The 7-parameter double-exponential model is applied in the modeling. The method is based on linear fitting of semi-logarithmic plots. The paper demonstrates a new technique to estimate the series resistance of a module with high accuracy from such plots. As a result, also the reverse saturation current and the quality factor of the diffusion diode can be determined. The method is applied to outdoor I–V data from a test station with three similar, but not identical, polycrystalline-Si modules. The values of the series resistances found with this method deviate somewhat from th…
Microwave Response of Coaxial Cavities Made of Bulk Magnesium Diboride
2014
We report on the microwave (mw) properties of coaxial cavities built by using bulk MgB2 superconductor prepared by reactive liquid Mg infiltration technology. We have assembled a homogeneous cavity, by using an outer MgB2 cylinder and an inner MgB2 rod, and a hybrid cavity by using an outer copper cylinder and the same MgB2 rod as inner conductor. By the analysis of the resonance curves, in the different resonant modes, we have determined the microwave surface resistance, Rs, of the MgB2 materials as a function of the temperature and the frequency, in the absence of DC magnetic fields. At T = 4.2 K and f = 2.5 GHz, by a mw pulsed technique, we have determined the quality factor of the homog…
The quality factor of a superconducting rf resonator in a magnetic field.
2010
The quality factor of a superconducting NbTi resonator at 1.6 MHz in a magnetic field up to 1.2 T as well as its temperature dependence is investigated. A hysteresis effect in the superconducting surface resistance as a function of the magnetic field is observed. An unloaded Q-value of the resonator of 40,500 is achieved at 3.9 K. It is shown that this Q-value is limited by dielectric losses in the FORMVAR insulation of the coils wire. The details of the Q-value optimization are discussed. In the temperature dependence of the Q-value a steep decrease is observed above T approximately = 7.5 K. Finally, the implications of these measurements for real trap experiments are discussed in detail.
Scattering loss analysis in PMMA WGM micro resonator from surface irregularities
2021
The following work shows new ways to analyze PMMA WGM micro resonators, that have irregularities, which acts as scattering centers. The scattering analyses could be used for integration into sensor systems and corrections of existing experiments.
Indoor free space optics link under the weak turbulence regime: Measurements and model validation
2015
In this study, the authors present the measurements performed on a free space optics (FSO) communications link using an indoor atmospheric chamber. In particular, the authors have generated several different optical turbulence conditions, demonstrating how even the weak turbulence regime can strongly affect the FSO link performance. The authors have carried out an in-depth analysis of the data collected during the measurements, and calculated the turbulence strength (i.e. scintillation index and Rytov variance) and the important performance metrics (i.e. the Q-factor and bit error rate) to evaluate the FSO link quality. Moreover, the authors have tested, for the first time, an appositely de…
Quality Factor Measurements for PMMA WGM Microsphere Resonators Using Fixed Wavelength Laser and Temperature Changes
2019
The whispering gallery modes (WGM) resonators are based on spherical objects, which are made from optically transparent materials, and are capable of maintaining circulating optical waves, inside the sphere, using total internal reflection. If there is a monochromatic light source which supplies the sphere with a constant intensity, the wave moving along the perimeter of sphere starts to constructively interfere. In this case the resonance happens, which is called whispering gallery mode (WGM). The current work explores the possibility of using temperature changes to measure polymethyl methacrylate (PMMA) WGM microsphere resonator quality factor (Q) and thermal expansion parameters. Differe…