A large-capacity, long-distance distributed acoustic sensing (DAS) system without inline optical amplification was proposed and experimentally demonstrated using an ultra-weak fiber Bragg grating (UWFBG) array and coherent detection. The effect of the finite extinction ratio of an acousto-optic modulator and the Stokes signal of stimulated Brillouin scattering (SBS) in UWFBGs on the performance of DAS was simulated and revealed. A high extinction ratio and a balanced input pulsed optical power can improve the capacity and distance of the DAS. The dynamic acoustic signal can be well reconstructed for a serial array of 10828 near-identical UWFBG with a length of 54.14 km. An acoustic signal sensitivity of 189.54 pɛ/√Hz and a signal SNR of 40.01 dB with a spatial resolution of 5 m can be achieved at the far end.
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http://dx.doi.org/10.1364/OE.455252 | DOI Listing |
The strain and deformation of bridges are important parameters to reflect the state of bridge structures. The traditional measurement methods are to obtain the partial strain of a bridge by point strain sensor or to obtain the deformation of some special bridge positions by static level and other methods. These methods can not realize the continuous distributed measurement of bridge stress state.
View Article and Find Full Text PDFIntegrating quantum key distribution (QKD) with classical optical communication is a deployment-friendly and cost-effective approach to advancing QKD network implementation. However, the noise introduced by intense classical signals into the quantum channel severely impacts the performance of the QKD system, presenting challenges for long-distance coexistence transmission. In this paper, we successfully demonstrate the simultaneous propagation of QKD and optical transport network (OTN) in the C-band over distances exceeding 100 km.
View Article and Find Full Text PDFNat Commun
April 2024
Key Laboratory for Information Science of Electromagnetic Waves (MoE), School of Information Science and Technology, Fudan University, Shanghai, China.
Due to its unique intensity distribution, self-acceleration, and beam self-healing properties, Airy beam holds great potential for optical wireless communications in challenging channels, such as underwater environments. As a vital part of 6G wireless network, the Internet of Underwater Things requires high-stability, low-latency, and high-capacity underwater wireless optical communication (UWOC). Currently, the primary challenge of UWOC lies in the prevalent time-varying and complex channel characteristics.
View Article and Find Full Text PDFNanomaterials (Basel)
November 2023
Key Laboratory of Engineering Dielectric and Applications, Ministry of Education, School of Electrical and Electronic Engineering, Harbin University of Science and Technology, Harbin 150080, China.
Currently, vortex beams are extensively utilized in the information transmission and storage of communication systems due to their additional degree of freedom. However, traditional terahertz metasurfaces only focus on the generation of narrowband vortex beams in reflection or transmission mode, which is unbeneficial for practical applications. Here, we propose and design terahertz metasurface unit cells composed of anisotropic -shaped metal structures, two dielectric layers, and a VO film layer.
View Article and Find Full Text PDFMolecules
June 2023
School of Chemistry and Chemical Engineering, Nantong University, Nantong 226019, China.
Direct current (DC) power transmission systems have received great attention because it can easily integrate many types of renewable energies and have low energy loss in long-distance and large-capacity power transmission for electricity global sharing. Nanoparticles (NPs) have a positive effect on the insulation properties of polymers, but weak interaction between NPs and polymer matrix greatly decreases the effort of NPs on the enhancement of insulation properties, and thereby limits its engineering application. In this work, grafting strategy was used to link the modified NPs and polymer matrix to improve their interactions.
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