View source for An assessment researchsupported group treating drug use issues

All-optical aggregation and de-aggregation with wavelength preserved play an important role in a flexible optical network. In addition, it is also expected to apply in a network node that connects different networks and increases the channel utilization by freeing up the low-speed channel. In this paper, we proposed an aggregation and de-aggregation setup between three binary phase shift keying signals and 8-ary quadrature amplitude modulation signal using the nonlinear effect in high nonlinear optical fiber. Moreover, the bit-error rate of the signal is analyzed to evaluate the performance of the system by numerical simulation.An optoelectronic optimization was carried out for an $ \rm Al_\xi \rm Ga_1 - \xi \rm As $AlξGa1-ξAs (AlGaAs) solar cell containing (i) an $ n $n-AlGaAs absorber layer with a graded bandgap and (ii) a periodically corrugated Ag backreflector combined with localized ohmic Pd-Ge-Au backcontacts. The bandgap of the absorber layer was varied either sinusoidally or linearly. An efficiency of 33.1% with the 2000-nm-thick $ n $n-AlGaAs absorber layer is predicted with linearly graded bandgap along with silver backreflector and localized ohmic backcontacts, in comparison to 27.4% efficiency obtained with homogeneous bandgap and a continuous ohmic backcontact. Sinusoidal grading of the bandgap is predicted to enhance the maximum efficiency to 34.5%. Thus, grading the bandgap of the absorber layer, along with a periodically corrugated Ag backreflector and localized ohmic Pd-Ge-Au backcontacts, can help realize ultrathin and high-efficient AlGaAs solar cells for terrestrial applications.A resonator fiber-optic gyro (RFOG) is being pursued because of its theoretical potential to meet navigation-grade performance with small size, high precision, and lower cost. The stability of the RFOG operation is based on the synchronization of laser frequency to the fiber ring resonator (FRR) resonance frequency. Frequency tracking out-of-lock will lead to peak pulse and zero-bias change at the output of the RFOG, which seriously degrades the performance. First, the influence mechanism of frequency tracking out-of-lock is analyzed. The change of current and temperature in frequency tracking and the symmetry change caused by backscatter and polarization are the main reasons for the peak pulse and zero-bias error. Second, a scheme of out-of-lock control of the RFOG based on temperature closed-loop operation using digital signal processing is proposed. The improved scheme, signal processing, and implementation method are investigated in detail. Finally, a RFOG prototype is assembled and tested, and 10 min tracking of the laser frequency to the FRR's single-resonance frequency is realized by temperature closed-loop operation. The static performance of the RFOG over 1 h shows that the RFOG output errors caused by frequency tracking out-of-lock are successfully eliminated. The output peak pulse is reduced from 3000 to 200 deg/h, the zero bias is eliminated from 50 to 600 deg/h to 0, and the bias stability of the RFOG is improved from 15.2 to 1.85 deg/h, which indicates a remarkable advance in the performance of the RFOG to satisfy civil navigation application requirements.White-light scanning interferometry (WLSI) is an important measurement technique that has been widely used in three-dimensional profile reconstruction. Because of the effects of environmental noise and phase changes caused by surface reflection, existing WLSI algorithms have problems in measurement accuracy and measurement speed. Addressing these problems, this paper proposes a fast template matching method to determine precisely the zero optical path difference (ZOPD) position in the WLSI. [https://www.selleckchem.com/products/CHIR-258.html TKI258] Due to the uniform shape of the interference signals, a template interference signal can be obtained in advance by performing a least-square fitting or Fourier interpolation on an interference signal of one pixel. In the method, the ZOPD position is initially obtained by the centroid method. Then, the ZOPD position is determined by a precise matching process through moving the template interference signal on the measured interference signal. Through the two-step processes, the ZOPD position can be obtained precisely with much less time. The method was simulated and verified through the measurement of a spherical surface, a 1.8-µm-height standard step and a flip-chip substrate. The experimental results show that the proposed algorithm can achieve both high precision and fast measurement.Adaptive-optics (AO) systems correct the optical distortions of atmospheric turbulence to improve resolution over long paths. In applications such as remote sensing, object tracking, and directed energy, the AO system's beacon is often an extended beacon reflecting off an optically rough surface. This situation produces speckle noise that can corrupt the wavefront measurements of the AO system, degrading its correction of the turbulence. This work studies the benefits of speckle mitigation via polychromatic illumination. To quantify the benefits over a wide range of conditions, this work uses a numerical wave-optics model with the split-step method for turbulence and the spectral-slicing method for polychromatic light. It assumes an AO system based on a Shack-Hartmann wavefront sensor. In addition, it includes realistic values for turbulence strength, turbulence distribution along the path, coherence length, extended-beacon size, and object motion. The results show that polychromatic speckle mitigation significantly improves AO system performance, increasing the Strehl ratio by 180% (from 0.10 to 0.28) in one case.We propose a snapshot spectral imaging method for the visible spectral range using two digital cameras placed side-by-side a regular red-green-blue (RGB) camera and a monochromatic camera equipped with a dispersive diffractive diffuser placed at the pupil of the imaging lens. While spectral imaging was shown to be feasible using a single monochromatic camera with a pupil diffuser [Appl. Opt.55, 432 (2016)APOPAI0003-693510.1364/AO.55.000432], adding an RGB camera provides more spatial and spectral information for stable reconstruction of the spectral cube of a scene. Results of optical experiments confirm that the combined data from the two cameras relax the complexity of the underdetermined reconstruction problem and improve the reconstructed image quality obtained using compressed sensing-based algorithms.