Top Research Papers on Telecommunication

Nanofabricated mechanical resonators are gaining significant momentum among\npotential quantum technologies due to their unique design freedom and\nindependence from naturally occurring resonances. With their functionality\nbeing widely detached from material choice, they constitute ideal tools to be\nused as transducers, i.e. intermediaries between different quantum systems, and\nas memory elements in conjunction with quantum communication and computing\ndevices. Their capability to host ultra-long lived phonon modes is\nparticularity attractive for non-classical information storage, both for...

Preface. 1. Introduction. 2. Optical Signal Generation. 3. Signal Propagation in Fibers. 4. Nonlinear Impairments. 5. Signal Recovery and Noise. 6. Optical Amplifier Noise. 7. Dispersion Management. 8. Nonlinearity Management. 9. WDM Systems. 10. Optical Networks. Appendix A: System of Units. Appendix B: Software Package. Appendix C: Acronyms. Index.

This paper represents customer’s daily behavior as multivariate time series and proposes four models to predict churn daily based on this representation and shows that the daily models significantly outperform the monthly models in terms of predicting churners earlier and more accurately.

Optoelectronic logic gates (OELGs) are promising building blocks for next-generation logic circuits and potential applications in light detection and ranging, machine vision and real-time video analysis. On-chip OELGs operating at telecom wavelengths are highly desirable for integration with the growing possibilities offered by silicon-based optoelectronics. However, at present operations are limited to linear logic functions in the ultraviolet or visible range and high-performance OELGs for multiple logic functions are lacking. Here we integrate up to three silicon waveguides with black phosp...

A key challenge in realizing practical quantum networks for long-distance quantum communication involves robust entanglement between quantum memory nodes connected by fibre optical infrastructure 1-3 . Here we demonstrate a two-node quantum network composed of multi-qubit registers based on silicon-vacancy (SiV) centres in nanophotonic diamond cavities integrated with a telecommunication fibre network. Remote entanglement is generated by the cavity-enhanced interactions between the electron spin qubits of the SiVs and optical photons. Serial, heralded spin-photon entangling gate operations wit...

Given its unrivaled potential of integration and scalability, silicon is\nlikely to become a key platform for large-scale quantum technologies.\nIndividual electron-encoded artificial atoms either formed by impurities or\nquantum dots have emerged as a promising solution for silicon-based integrated\nquantum circuits. However, single qubits featuring an optical interface needed\nfor large-distance exchange of information have not yet been isolated in such a\nprevailing semiconductor. Here we show the isolation of single optically-active\npoint defects in a commercial silicon-on-insulator wafer...

Abstract Quantum networks promise to provide the infrastructure for many disruptive applications, such as efficient long-distance quantum communication and distributed quantum computing 1,2 . Central to these networks is the ability to distribute entanglement between distant nodes using photonic channels. Initially developed for quantum teleportation 3,4 and loophole-free tests of Bell’s inequality 5,6 , recently, entanglement distribution has also been achieved over telecom fibres and analysed retrospectively 7,8 . Yet, to fully use entanglement over long-distance quantum network links it is ...

An unprecedented external device conversion efficiency of 57% is achieved and an entanglement fidelity between the atom and telecom photon of ≥78.5±0.9% after transmission through 20 km of optical fiber is observed, an important milestone on the road to distribute quantum information on a large scale.

Long-distance entanglement distribution is a vital capability for quantum technologies. An outstanding practical milestone towards this aim is the identification of a suitable matter-photon interface that possesses, simultaneously, long coherence lifetimes and efficient telecommunication-band optical access. In this work we report upon the T center, a silicon defect with long-lived spins and spin-selective bound exciton optical transitions at 1326 nm in the telecommunications O-band. In this first study of T centers in 28 Si, we present the temperature dependence of the zero-phonon line, repor...

This realization is extendable to entanglement over longer distances and provides a viable route towards field-deployed, multiplexed quantum repeaters based on solid-state resources.

Metasurfaces have seen a great evolution over the last few years, demonstrating a high degree of control over the amplitude, phase, polarization, and spectral properties of reflected or transmitted electromagnetic waves. Nevertheless, the inherent limitation of static metasurface realizations, which cannot be controlled after their fabrication, engages an ongoing pursuit for reconfigurable metasurfaces with profound tunability. In this paper, we mitigate this grand challenge by demonstrating a new method for free-space rapid optical tunability and modulation, utilizing a planar aluminum nanodi...

A 1D passive silicon photonic metasystem with near 90% spatial pattern classification accuracy at telecommunication wavelength is reported.

As the core driving force of the new round of informatization development and industrial revolution, the disruptive achievements of artificial intelligence (AI) are rapidly and comprehensively comprehensively integrated into the fabric of society.

Atomic defects in the solid state are a key component of quantum repeater networks for long-distance quantum communication 1 . Recently, there has been significant interest in rare earth ions 2-4 , in particular Er 3+ for its telecom band optical transition 5-7 that allows long-distance transmission in optical fibres. However, the development of repeater nodes based on rare earth ions has been hampered by optical spectral diffusion, precluding indistinguishable single-photon generation. Here, we implant Er 3+ into CaWO 4 , a material that combines a non-polar site symmetry, low decoherence fro...

The COVID-19 pandemic substantially impacted the field of telecommunication. It increased the use of media applications that enable teleconferencing, telecommuting, online learning, and social relations. Prolonged time facing screens, tablets, and smart devices increases stress and anxiety. Mental health stressors associated with telecommunication can add to other stressors related to quarantine time and lockdown to eventually lead to exhaustion and burnout. In this review, the effects of the COVID-19 pandemic on communication and education are explored. In addition, the relationship between p...

This paper aims to explore dimensionality reduction on a real telecom dataset and evaluate customers’ clustering in reduced and latent space, compared to original space in order to achieve better quality clustering results.

Abstract Dispersion engineering is essential to the performance of most modern optical systems including fiber-optic devices. Even though the chromatic dispersion of a meter-scale single-mode fiber used for endoscopic applications is negligible, optical lenses located on the fiber end face for optical focusing and imaging suffer from strong chromatic aberration. Here we present the design and nanoprinting of a 3D achromatic diffractive metalens on the end face of a single-mode fiber, capable of performing achromatic and polarization-insensitive focusing across the entire near-infrared telecomm...

In this proposed model, two machine-learning techniques were used for predicting customer churn Logistic regression and Logit Boost were used.

Note: It should be mentioned that Rectna has been studied in recent years, especially in the matter of power transmission in the microwave band. For example, in theory, for a single frequency of 9.2 GHz, more than 10% efficiency is predicted .Of course, this is the fact that the practical efficiency of making these materials may be slightly different and should be determined in practice. The dipole antenna with linear polarization and 2/λ length, which has a relative bandwidth of 11%, will be able to collect about pW 75.2. For this reason, if using an antenna with double polarization, the powe...

Data centres (DCs) and telecommunication base stations (TBSs) are energy intensive with ∼40% of the energy consumption for cooling. Here, we provide a comprehensive review on recent research on energy-saving technologies for cooling DCs and TBSs, covering free-cooling, liquid-cooling, two-phase cooling and thermal energy storage based cooling. The power usage effectiveness (PUE) and energy savings rate (ESR) data of the DCs and TBSs are analysed and compared with specific attention paid to the difference between the laboratory and commercial systems. The results indicate that the immersion liq...

The public health impact of out-of-hospital cardiac arrest is described, guidance and resources are provided to construct and maintain a T-CPR program, the minimal acceptable standards for timely and high-quality delivery of T- CPR instructions are outlined, and strategies to overcome common implementation barriers are identified.

High-performance vertical van der Waals heterostructure-based photodetectors integrated on a silicon photonics platform that minimizes the carrier transit path length in TMDCs and enables a record-high measured bandwidth, shed light on performance trade-offs and present design guidelines for fast and efficient devices.

Single photon detectors are indispensable tools in optics, from fundamental measurements to quantum information processing. The ability of superconducting nanowire single photon detectors (SNSPDs) to detect single photons with unprecedented efficiency, short dead time, and high time resolution over a large frequency range enabled major advances in quantum optics. However, combining near-unity system detection efficiency (SDE) with high timing performance remains an outstanding challenge. In this work, we fabricated novel SNSPDs on membranes with 99.5−2.07+0.5% SDE at 1350 nm with 32 ps timing ...

5G and forthcoming 6G communication systems require dielectric ceramics with low relative permittivity (εr) and near-zero temperature coefficient of resonant frequency (τf) for the lower part of the microwave (MW) band and at sub-Terahertz. Mg2Al4Si5O18 (MAS) ceramics are promising candidates due to their low εr (~ 6) and high-quality factor (Q×f > 40,000 GHz) but have a large τf. In this study, 5.5 wt% TiO2 (MAS-T5.5) was used to adjust τf of MAS to −2.8 ppm/℃ whilst retaining low εr (5.24) and good Q×f (33,400 GHz), properties consistent with those obtained by infrared reflectance. A demonst...

Telecommunications infrastructure can lead to network spillovers and has the advantages of breaking spatial barriers, reducing transaction costs, and fostering business model innovation. In this way, it can promote the proliferation and progress of green technology and may impact green technology innovation. This paper studies the impact of telecommunications infrastructure on green technology innovation, identifies its mechanism, and analyzes the scale, structure, and heterogeneity of its effects. This research treats the Broadband China pilot policy as a quasinatural experiment in telecommun...

Informatization and digitization have become breakthrough topics in China's economic development and environmental governance. In the same vein, knowledge, technology spillovers, and economic agglomeration effects of telecommunications infrastructure may enhance eco-efficiency. This study adopts the heterogeneous timing difference-in-difference (DID) model and event study method to evaluate the impact of telecommunications infrastructure on eco-efficiency using city-level data from 2008 to 2018 and the quasi-natural experiment of the Broadband China policy. The results indicate that telecommun...

This work reports the first solution processed laser, comprising PbS colloidal quantum dots (CQDs) integrated on a distributed feedback (DFB) cavitiy, with tuneable lasing wavelength from 1.55 μm - 1.65 μm, operating at room temperature and exhibit linewidths as low as ~0.9 meV.

The formulation of strategic alliance by commercial, social and government organizations has potential to imultaneously achieve market related success and develop solution to social problems. Social innovation that leads to positive changes in society by providing solutions to social and environmental challenges may also require strategic collaboration by multiple organizations. Despite recent scholarly interest in social innovation, there is scant empirical evidence on the underlying drivers of network-based sustainable strategic relationships that co-create value. Moreover, further academic ...

Customer focus strategy has shifted the way the businesses shape their customer satisfaction.Service oriented companies in general have been given a great emphasis and a significance care to both customer satisfaction and customer delight lately.However, the management decision of what to offer to gain customer happiness is still a challenge issue.To test such issue, this study develops and tests a set of new factors which shapes both customer satisfaction and delight within the UAE setting.The factors include perceived service value, perceived service quality, perceived price fairness in addi...