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We analyze the properties of chirped optical X-shaped pulses propagating in material media without boundaries. We show that such ("superluminal") pulses may recover their transverse and longitudinal shapes after some propagation distance, whereas the ordinary chirped Gaussian pulses can recover their longitudinal width only (since Gaussian pulses suffer a progressive transverse spreading during their propagation). We therefore propose the use of chirped optical X-type pulses to overcome the problems of both dispersion and diffraction during pulse propagation.
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http://dx.doi.org/10.1364/josaa.21.002455 | DOI Listing |
Rev Sci Instrum
August 2025
Synchrotron SOLEIL, L'Orme des Merisiers, Départementale 128, 91190 Saint Aubin, France.
The surface quality of x-ray mirrors is a major constraint on optical performance at synchrotron light and free electron laser facilities. A limiting factor for creating state-of-the-art optics is the accuracy of metrology data to deterministically guide the polishing tool to correct surface errors. The "MooNpics" (Metrology On One-Nanometer-Precise Optics) collaboration aims to improve optical metrology capabilities at European facilities to enable reproducible measurement of long or curved optics with height errors <1 nm rms and slope errors <100 nrad rms.
View Article and Find Full Text PDFOptical Frequency Domain Reflectometry (OFDR) has emerged as a core technology in the field of distributed fiber-optic sensing due to its advantages of high spatial resolution and large dynamic range. However, the traditional cross-correlation demodulation algorithm is excessively high, resulting in a significant degradation of the system's real-time performance. Here we propose an efficient cross-correlation algorithm based on the Chirp-Z Transform, which significantly reduces computational complexity.
View Article and Find Full Text PDFNeuromorphic photonic computing based on spiking dynamics holds significant promise for next-generation AI accelerators, enabling high-speed, low-latency, and low-energy computing. However, the architecture of neuromorphic photonic systems is severely constrained by large-scale discrete devices. In this work, we propose a photonic spiking neural network (PSNN) architecture utilizing a directly modulated laser and a distributed feedback laser with a saturable absorber (DML-DFB-SA).
View Article and Find Full Text PDFRadar has become a widely adopted technology in intelligent transportation systems for environmental sensing. However, the exponential increase in the number and functionality of radars, combined with the dynamic traffic scenarios, made the radar's operating scenarios complex and variable, imposing significant challenges on the radar's operation. In this paper, we propose a stimulated Brillouin scattering (SBS) based self-adaptive time-frequency signal processing (TFSP) method for dynamic interference scenarios, which can adapt to suppress the high-power interference and enhance the operation performance of radar systems.
View Article and Find Full Text PDFWe present and experimentally demonstrate a 20-channel electroabsorption-modulated DFB laser (EML) array, designed as a compact, cost-effective single-chip solution for 1 Tb/s transmitters, targeted for high-performance data center applications, particularly in artificial intelligence (AI) systems. The array utilizes a shared InGaAlAs multiple-quantum-well (MQW) active layer for both the distributed feedback (DFB) lasers and electroabsorption modulators (EAM), enabling a simplified and economically viable monolithic integration. The reconstruction equivalent chirp (REC) technique is used to simplify the grating fabrication and precisely control the wavelength spacing.
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