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Related papers: Ultra-wideband free-space optical phase stabilisat…

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With the evolution of mobile communication systems toward large-scale arrays, high-frequency operation, and reconfigurable antenna architectures, fluid antenna systems (FAS) operating in the near-field (NF) regime provide new degrees of…

Information Theory · Computer Science 2026-05-12 Peng Zhang , Jian Dang , Miaowen Wen , Ziyang Liu , Chen Zhao , Huaifeng Shi , Chengsheng Pan , Zaichen Zhang

This paper investigates the average symbol error rate (ASER) performance of a dual-hop hybrid relaying system relying on both radio frequency (RF) and free space optical (FSO) links. Specifically, the RF link is used for supporting mobile…

Information Theory · Computer Science 2015-08-26 Lei Kong , Wei Xu , Lajos Hanzo , Hua Zhang , Chunming Zhao

Second generation quantum technologies aim to outperform classical alternatives by utilizing engineered quantum systems. Maintaining the coherence required to enable any quantum advantage requires detailed knowledge and control over the…

Quantum Physics · Physics 2024-05-30 Robert Freund , Christian D. Marciniak , Thomas Monz

We develop a system for measurements of power spectra of transmitted light intensity fluctuations, in which the extraneous noise, including shot noise, is reduced. In essence, we just apply light, measure the power of the transmitted light…

Atomic Physics · Physics 2023-07-19 Takahisa Mitsui , Kenichiro Aoki

We present an experimental technique allowing to stabilize the frequency of the non resonant wave in a singly resonant optical parametric oscillator (SRO) down to the kHz level, much below the pump frequency noise level. By comparing the…

Optics · Physics 2015-06-11 Aliou Ly , Benjamin Szymanski , Fabien Bretenaker

In this paper, we investigate the impact of phase noise on the secrecy performance of downlink massive MIMO systems in the presence of a passive multiple-antenna eavesdropper. Thereby, for the base station (BS) and the legitimate users, the…

Information Theory · Computer Science 2016-11-17 Jun Zhu , Robert Schober , Vijay K. Bhargava

The most frequency-stable sources of electromagnetic radiation are produced optically, and optical frequency combs provide the means for high fidelity frequency transfer across hundreds of terahertz and into the microwave domain. A critical…

Free-space communication links are severely affected by atmospheric turbulence, which causes degradation in the transmitted signal. One of the most common solutions to overcome this is to exploit diversity. In this approach, information is…

Signal Processing · Electrical Eng. & Systems 2018-08-22 Mitchell A. Cox , Carmelo Rosales-Guzmán , Ling Cheng , Andrew Forbes

Aerial suspended optical-fiber links are being considered as economical alternatives to buried links for long-distance transfer of coherent time and frequency signals. We present stability measurements of an actively stabilized 20 MHz…

Instrumentation and Detectors · Physics 2017-06-15 David Gozzard , Sascha Schediwy , Bruce Wallace , Romeo Gamatham , Keith Grainge

Weight reduction and low power consumption are key requirements in the next generation of unmanned aerial vehicle (UAV) networks. Employing modulating retro-reflector (MRR)-based free space optical (FSO) technology is an innovative…

Signal Processing · Electrical Eng. & Systems 2022-03-15 Mohammad Taghi Dabiri , Mohsen Rezaee , Leila Mohammadi , Farhang Javaherian , Vahid Yazdanian , Mazen Omar Hasna , Murat Uysal

The free-space optical channel has the potential to facilitate inexpensive, wireless communication with fiber-like bandwidth under short deployment timelines. However, atmospheric effects can significantly degrade the reliability of a…

Information Theory · Computer Science 2008-04-02 Nick Letzepis , Albert Guillen i Fabregas

With the advent of sixth-generation networks, reconfigurable intelligent surfaces (RISs) have revolutionized wireless communications through dynamic electromagnetic wave manipulation, thereby facilitating the adaptability and unparalleled…

Information Theory · Computer Science 2024-08-13 Md. Abdur Rakib , Md. Ibrahim , A. S. M. Badrudduza , Imran Shafique Ansari , Md. Shahid Uz Zaman , Heejung Yu

Measurements of optical range and time-of-flight are crucial for a variety of high-precision technologies. Competitive optical measurement techniques have been developed that balance precision with accuracy and system complexity. Here, we…

We present experimental data on message transmission in a free-space optical (FSO) link at an eye-safe wavelength, using a testbed consisting of one sender and two receiver terminals, where the latter two are a legitimate receiver and an…

In this paper, we propose a novel free-space optical (FSO) communication system utilizing optical skyrmions. We introduce a scheme referred to as skyrmion number modulation (SkM), which employs index modulation by encoding information onto…

Signal Processing · Electrical Eng. & Systems 2026-03-13 Ryosuke Hara , Satoshi Iwamoto , Shinya Sugiura

Amplification is usually necessary when measuring the frequency instability of microwave signals. In this work, we develop a flicker noise free frequency measurement system based on a common or shared amplifier. First, we show that…

Instrumentation and Detectors · Physics 2012-02-23 Daniel L. Creedon , Michael E. Tobar , Eugene N. Ivanov , John G. Hartnett

We demonstrate the distribution of single-photon-level pulses from a mode-locked laser source over a phase-stable fiber link, achieving an optical timing jitter of less than 100 as over 10 minutes of data accumulation. This stability…

The present work analyzes state-stabilization techniques for decoupling a subsystem from environmental interactions. The proposed framework uses analytical and numerical tools to find an approximate decoherence-free subspace (DFS) with…

Quantum Physics · Physics 2025-07-11 Miguel Casanova , Francesco Ticozzi

We observed continuous-variable entanglement between the bright beams emitted above threshold by an ultrastable optical parametric oscillator, classically phase-locked at a frequency difference of 161.8273240(5) MHz. The…

Quantum Physics · Physics 2009-11-13 Jietai Jing , Sheng Feng , Russell Bloomer , Olivier Pfister

We describe a fiber-optic solution for simultaneous distribution of all signals generated at todays most advanced time and frequency laboratories, i.e. an ultrastable optical reference frequency derived from an optical atomic clock, a radio…

Applied Physics · Physics 2017-06-07 P. Krehlik , H. Schnatz , L. Sliwczynski