We studied the amplitude and phase noise suppression properties of an all-optical regenerator for differential phase-shift keying data. A detailed analytical investigation is performed and compared with numerical simulations for different working points. The results show that both amplitude and phase can be regenerated. However, simultaneous amplitude and phase noise suppression is possible only if the phase degradation is stronger than the amplitude degradation, for instance, due to nonlinear phase noise.
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http://dx.doi.org/10.1364/ol.32.000112 | DOI Listing |
Lensless imaging offers a lightweight, compact alternative to traditional lens-based systems, ideal for exploration in space-constrained environments. However, the absence of a focusing lens and limited lighting in such environments often results in low-light conditions, where the measurements suffer from complex noise interference due to insufficient capture of photons. This study presents a robust reconstruction method for high-quality imaging in low-light scenarios, employing two complementary perspectives: model-driven and data-driven.
View Article and Find Full Text PDFCoherent lensless imaging usually suffers from coherent noise and twin-image artifacts. In the terahertz (THz) range, where wavelengths are 2 to 4 orders of magnitude longer than those in the visible spectrum, the coherent noise manifests primarily as parasitic interference fringes and edge diffraction, rather than speckle noise. In this work, to suppress the Fabry-Pérot (F-P) interference fringes, we propose a novel method, which involves the averaging over multiple diffraction patterns that are acquired at equal intervals within a sample's half-wavelength axial shift.
View Article and Find Full Text PDFBroadband minimalist wireless base stations without energy-consuming electrical power amplifiers are the rosy scenario of the next-generation wireless communication systems. High-power radio-over-fiber (RoF) links, which are featured by large operation bandwidths, are regarded as the supporting technology for realizing such a vision. Nevertheless, the severe signal-to-noise ratio (SNR) deterioration induced by the second Brillouin scattering in high-power and long-distance RoF links must be first solved.
View Article and Find Full Text PDFThis paper presents an adaptive fast Fourier transform (adaptive FFT) demodulation scheme, aimed at enhancing the precision and noise suppression capability of signal processing in fiber-optic interferometric sensors. By adaptively optimizing the length of the acquired spectrum and dynamically adjusting the frequency domain resolution, the proposed scheme can precisely calculate the eigenfrequency of the reflected spectrum. Therefore, the adaptive FFT demodulation scheme can effectively enhance the extraction ability of phase quadrature demodulation signal.
View Article and Find Full Text PDFDistributed acoustic sensing (DAS) is a technology that uses optical fiber as a sensing unit to detect external vibration signals. Due to the high resolution and high sensitivity of DAS, it has great application potential in the detection of vibration events. However, high detection performance will bring limitations to DAS in multi-source detection.
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