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Traditional wireless communication methods tend to saturate in terms of data rate, frequency spectrum and reliability. Visible Light Communication (VLC) integrated with the emerging technology of Internet-of-Things (IoT) opens up to a wide range of indoor applications. In this work we will describe the potential of an optical wireless communication infrastructure and we will make a comparison with the emerging 5G and 6G Wi-Fi (RF) technologies.

In scientific, military, and industrial sectors, the development of robust and efficient submarine wireless communication links is of enormous interest. Underwater wireless communications can be carried out through acoustic, radio frequency (RF), and optical waves. Underwater optical communication is not a new idea, but it has recently been considered because seawater exhibits a window of reduced absorption both in the visible spectrum and long-wavelength UV light (UV-A). Compared to its bandwidth limited acoustic counterpart, underwater optical wireless communications (UOWCs) can support higher data rates at low latency levels. Underwater wireless communication networks are important in ocean exploration, military tactical operations, environmental and water pollution monitoring. Anyway, given the rapid development of UOWC technology, documents are still needed showing the state of the art and the progress made by the most current research. This paper aims to examine current technologies, and those potentially available soon, for Underwater Optical Wireless Communication and to propose a new perspective using UV-A radiation.

For military divers, having a robust, secure, and undetectable wireless communication system available is a fundamental element. Wireless intercoms using acoustic waves are currently used. These systems, even if reliable, have the defect of being easily identifiable and detectable. Visible light can pass through sea water. Therefore, light can be used to develop short-range wireless communication systems. To realize secure close-range underwater wireless communication, the Underwater Optical Wireless Communication (UOWC) can be a valid alternative to acoustic wireless communication. UOWC is not a new idea, but the problem of the presence of sunlight and the possibility of using near-ultraviolet radiation (near-UV) has not been adequately addressed in the literature yet. In military applications, the possibility of using invisible optical radiation can be of great interest. In this paper, a feasibility study is carried out to demonstrate that UOWC can be performed using near-ultraviolet radiation. The proposed system can be useful for wireless voice communications between military divers as well as amateur divers.

В работе предлагается структурная схема устройства обнаружения канала утечки информации, путем изменения интенсивности осветительных светодиодов. Приводится обоснование возможных реализаций структурных блоков устройства., This paper proposes a block diagram of a device for detecting a channel of information leakage by changing the intensity of lighting LEDs. The substantiation of possible implementations of structural units of the device is given.

ICARUS T600 is the far detector of the Short Baseline Neutrino program at Fermilab (U.S.A.), which foresees three Liquid Argon Time Projection Chambers along the Booster Neutrino Beam line to search for LSND-like sterile neutrino signal. The T600 detector underwent a significant overhauling process at CERN, introducing new technological developments while maintaining the already achieved performances. The realization of a new liquid argon scintillation light detection system is a primary task of the detector overhaul. As the detector will be subject to a huge flux of cosmic rays, the light detection system should allow the 3D reconstruction of events contributing to the identification of neutrino interactions in the beam spill gate. The design and implementation of the new scintillation light detection system of ICARUS T600 is described. ICARUS T600 is the far detector of the Short Baseline Neutrino program at Fermilab(USA), which foresees three Liquid Argon Time Projection Chambers along the Booster Neutrino Beam line to search for LSND-like sterile neutrino signal. The T600 detector underwent a significant overhauling process at CERN, introducing new technological developments while maintaining the already achieved performances. The realization of a new liquid argon scintillation light detection system is a primary task of the detector overhaul. As the detector will be subject to a huge flux of cosmic rays, the light detection system should allow the 3D reconstruction of events contributing to the identification of neutrino interactions in the beam spill gate. The design and implementationof the new scintillation light detection system of ICARUS T600 is described.

We report the design, fabrication, and test of an InGaAs avalanche photodiode (APD) for 950–1650 nm wavelength sensing applications. The APD is grown by molecular beam epitaxy on InP substrates from lattice-matched InGaAs and InAlAs alloys. Avalanche multiplication inside the APD occurs in a series of asymmetric gain stages whose layer ordering acts to enhance the rate of electron-initiated impact ionization and to suppress the rate of hole-initiated ionization when operated at low gain. The multiplication stages are cascaded in series, interposed with carrier relaxation layers in which the electric field is low, preventing avalanche feedback between stages. These measures result in much lower excess multiplication noise and stable linear-mode operation at much higher avalanche gain than is characteristic of APDs fabricated from the same semiconductor alloys in bulk. The noise suppression mechanism is analyzed by simulations of impact ionization spatial distribution and gain statistics, and measurements on APDs implementing the design are presented. The devices employing this design are demonstrated to operate at linear-mode gain in excess of 6000 without avalanche breakdown. Excess noise characterized by an effective impact ionization rate ratio below 0.04 were measured at gains over 1000.