Weinerlutz5683

Compared with the results of the peak height method, the results showed that the peak area was more accurate than the peak height in predicting the redshift of the UV spectrum.We experimentally demonstrate a degenerate mode-division multiplexing transmission system with single-sideband Nyquist pulse-shaped pulse amplitude modulation-4 and direct detection techniques. Hilbert superposition cancellation (HSC) processing is applied to cancel the first-order cross talk at the receiver side. A least mean square Volterra-based multiple-input, multiple-output (MIMO) nonlinear equalizer (NLE) is used to compensate the second-order distortion. Experimental results show that compared with the MIMO linear equalizer without HSC processing, the MIMO NLE with HSC processing can help improve the bit error rate performance by almost 1 order of magnitude at the received optical power of $ - 10\;\rm dBm$-10dBm.This paper presents a simple photonic-assisted instantaneous microwave frequency measurement approach with an adjustable measurement range. In our scheme, different polarization processing is performed on the upper and the lower branches, and then the powers of the two branches are compared to obtain the amplitude comparison function (ACF), which provides the frequency-amplitude mapping. The measurement system is significantly simplified since only one polarization modulator (PolM) and one single laser source are required. In addition, our scheme achieves a larger ACF slope, which significantly increases the measurement resolution. In the simulation, a frequency measurement over the range of 3-42.8 GHz with measurement errors within $\pm 0.1\;\rm GHz$±0.1GHz is achieved by optimizing the dc bias voltage applied to the PolM and the polarization angle. This scheme provides a reference for measuring the unknown instantaneous frequency of the received signal from a radar system.We numerically investigate phase-sensitive amplification of a quadrature phase shift keying (QPSK) signal in a 35 µm dispersion engineered silicon-graphene oxide hybrid waveguide. The four-wave mixing efficiency is effectively enhanced by exploiting the ultrahigh Kerr nonlinearity and low loss of graphene oxide in the ultrawide wavelength range. A new structure of dispersion flat silicon-graphene oxide hybrid waveguide is proposed and used to achieve the phase regeneration of a QPSK signal using a dual-conjugated-pump degenerate scheme. The phase-dependent gain and phase-to-phase transfer functions are calculated to analyze the properties of a phase-sensitive amplifier (PSA). The constellation diagrams of the QPSK signal and the error vector magnitude are used to assess the regeneration capacity. The simulation results show that the proposed PSA with a good phase noise squeezing capability has potential applications in all-optical signal processing.The phase information provided by the beat note between frequency combs and two continuous-wave lasers is used to extrapolate the phase evolution of comb modes found in a spectral region obtained via nonlinear broadening. This thereafter enables using interferogram self-correction to fully retrieve the coherence of a dual-comb beat note between two independent fiber lasers. This approach allows the $ f - 2f $f-2f self-referencing of both combs, which is a significant simplification. Broadband near-infrared methane spectroscopy has been conducted to demonstrate the simplified system's preserved performance.Low-power, lightweight, off-the-shelf imaging spectrometers, deployed on above-water fixed platforms or on low-altitude aerial drones, have significant potential for enabling fine-scale assessment of radiometrically derived water quality properties (WQPs) in oceans, lakes, and reservoirs. In such applications, it is essential that the measured water-leaving spectral radiances be corrected for surface-reflected light, i.e., glint. However, noise and spectral characteristics of these imagers, and environmental sources of fine-scale radiometric variability such as capillary waves, complicate the glint correction problem. Despite having a low signal-to-noise ratio, a representative lightweight imaging spectrometer provided accurate radiometric estimates of chlorophyll concentration-an informative WQP-from glint-corrected hyperspectral radiances in a fixed-platform application in a coastal ocean region. Optimal glint correction was provided by a spectral optimization algorithm, which outperformed both a hardware solution utilizing a polarizer and a subtractive algorithm incorporating the reflectance measured in the near infrared. In the same coastal region, this spectral optimization approach also provided the best glint correction for radiometric estimates of backscatter at 650 nm, a WQP indicative of suspended particle load.We describe the development of a near-infrared laser heterodyne radiometer the precision heterodyne oxygen-corrected spectrometer (PHOCS). The prototype instrument is equipped with two heterodyne receivers for oxygen and water (measured near 1278 nanometers) and carbon dioxide (near 1572 nanometers) concentration profiles, respectively. The latter may be substituted by a heterodyne receiver module equipped with a laser to monitor atmospheric methane near 1651 nanometers. Oxygen measurements are intended to provide dry gas corrections and-more importantly-determine accurate temperature and pressure profiles that, in turn, improve the precision of the $\rm CO_2$CO2 and $\rm H_2\rm O$H2O column retrievals. Vertical profiling is made feasible by interrogating the very low-noise absorption lines shapes collected at $ \approx 0.0067\;\rm cm^ - 1$≈0.0067cm-1 resolution. PHOCS complements the results from the Orbiting Carbon Observatory (OCO-2), Active Sensing of $\rm CO_2$CO2 Emissions over Nights, Days, and Seasons (ASCENDS), and ground-based Fourier transform spectrometers. In this paper, we describe the development of the instrument by Mesa Photonics and present the results of initial tests in the vicinity of Washington, DC.In the presence of direct sunlight or superbright light from artificial optical sources, the distribution of light intensity (brightness) over perceived scene objects typically has a dynamic range several orders of magnitude greater than the dynamic range of most optical sensors. In this paper, the locally adaptive optical protection (LAOP) filtering systems for technical vision sensors and human eyes (human visual system) are suggested. Selleck Ipatasertib The LAOP filtering provides the reliable perception of the perceived scene objects with normal brightness simultaneously with preventing saturation ("blinding") of the optical sensors by light from the brightest objects. The characteristics of the key components of the LAOP filtering systems are discussed and tested experimentally.