Orbital angular momentum modes emission from a silicon photonic integrated device for km-scale data-carrying fiber transmission

We experimentally demonstrate orbital angular momentum (OAM) modes emission from a high emission efficiency OAM emitter for 20-Gbit/s quadrature phase-shift keying (QPSK) carrying data transmission in few-mode fiber (FMF). The device is capable of emitting vector optical vortices carrying well-defined OAM efficiently with the efficiency of the device >37%. Seven modes propagate through a 2-km two-mode and a 3.6-km three-mode FMF with measured optical signal-to-noise ratio (OSNR) penalties less than 4 dB at a bit-error rate (BER) of 2 x 10(-3). The demonstrations with favorable performance pave the way to incorporate silicon photonic integrated devices as transceivers in an OAM-enabled optical fiber communication link. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreemen

Interconnection network architectures based on integrated orbital angular momentum emitters

Novel architectures for two-layer interconnection networks based on concentric OAM emitters are presented. A scalability analysis is done in terms of devices characteristics, power budget and optical signal to noise ratio by exploiting experimentally measured parameters. The analysis shows that by exploiting optical amplifications, the proposed interconnection networks can support a number of ports higher than 100. The OAM crosstalk induced-penalty, evaluated through an experimental characterization, do not significantly affect the interconnection network performance

The Orbital Angular Momentum of Light for Ultra-High Capacity Data Centers

The potential of orbital angular momentum (OAM) of light in data center scenarios is presented. OAMs can be exploited for short reach ultra-high bit rate fiber links and as additional multiplexing domain in transparent ultra-high capacity optical switches. Recent advances on OAM integrated photonic technology are also reported. Finally demonstration of OAM-based fiber links (aggregate throughput 17.9 Tb/s) and two layers OAM-WDM-based optical switches are presented exploiting OAM integrated components and demonstrating the achievable benefits in terms of size, weight and power consumption (SWaP) compared to different technologies

Optical Communication

Optical communication is very much useful in telecommunication systems, data processing and networking. It consists of a transmitter that encodes a message into an optical signal, a channel that carries the signal to its desired destination, and a receiver that reproduces the message from the received optical signal. It presents up to date results on communication systems, along with the explanations of their relevance, from leading researchers in this field. The chapters cover general concepts of optical communication, components, systems, networks, signal processing and MIMO systems. In recent years, optical components and other enhanced signal processing functions are also considered in depth for optical communications systems. The researcher has also concentrated on optical devices, networking, signal processing, and MIMO systems and other enhanced functions for optical communication. This book is targeted at research, development and design engineers from the teams in manufacturing industry, academia and telecommunication industries

High Bit Rate Wireless and Fiber-Based Terahertz Communication

RÉSUMÉ Dans le spectre électromagnétique, la bande des térahertz s’étend de 100 GHz à 10 THz (longueurs d’onde de 3 mm à 30 μm). Des décennies auparavant, le spectre des THz était connu sous le nom de « gap térahertz » en raison de l’indisponibilité de sources et détecteurs efficaces à ces fréquences. Depuis quelques années, la science a évolué pour faire migrer la technologie THz des laboratoires aux produits commerciaux. Il existe plusieurs applications des ondes THz en imagerie, spectroscopie et communications. Dans cette thèse, nous nous intéressons aux communications THz à travers deux objectifs. Le premier objectif est de développer une source THz de haute performance dédiée aux communications et basée sur les technologies optiques avec des produits commerciaux uniquement. Le second objectif est de démontrer l’utilisation de fibres optiques afin de renforcer la robustesse des communications THz sans fil. Nous débutons cette thèse avec une revue de la littérature scientifique sur le sujet de la communications THz sans fil et filaire. D’abord, nous discutons des deux méthodes communément utilisées (électronique et optique) pour démontrer des liens de communications THz avec leurs avantages et inconvénients. Nous présentons par la suite la possibilité d’utiliser un système de spectroscopie THz pour des applications en communications avec des modifications mineures au montage. Nous présentons ensuite plusieurs applications gourmandes en bande passante qui pourraient bénéficier du spectre THz, incluant la diffusion en continu (streaming) de flux vidéo aux résolutions HD et 4K non compressés. Ensuite, nous discutons de la motivation d’utiliser de longues fibres THz et notamment du fait qu’elles ne sont pas destinées à remplacer les fibres optiques conventionnelles de l’infrarouge, mais plutôt à augmenter la robustesse des liens THz sans fil. En particulier, les fibres THz peuvent être utilisées pour garantir le lien de communication dans des environnements géométriques complexes ou difficile à atteindre, ainsi que pour immuniser le lien THz aux attaques de sécurité. Plusieurs designs de fibres et guides d’onde précédemment démontrées dans la littérature sont discutés avec, entre autres, leurs méthodes de fabrication respectives. Nous discutons ensuite de la possibilité d’utiliser un simple guide d’onde diélectrique et sous-longueur d’onde pour transmettre l’information à un débit de l’ordre de plusieurs Gbps sur une distance de quelques mètres.----------ABSTRACT The Terahertz (THz) spectral range spans from 100 GHz to 10 THz (wavelength: 3 mm to 30 μm) in the electromagnetic spectrum. Decades ago, the THz spectral range is often named as ‘THz gap’ due to the non-availability of efficient THz sources and detectors. In the recent years, the science has evolved in bringing the THz technology from lab scale to commercial products. There are several potential applications of THz frequency band such as imaging, spectroscopy and communication. In this thesis, we focus on THz communications by addressing two objectives. The first objective is to develop a high-performance photonics-based THz communication system using all commercially available components. The second objective is to demonstrate the THz-fiber based communications, which can be used to increase the reliability of THz wireless links. We begin this thesis with a scientific literature review on the subject of THz wireless and fiber-based communications. First, the two different methodologies (all electronics based and photonics-based THz system) that is commonly used in the demonstration of THz communications is discussed along with their advantages and challenges. We then present the flexibility of photonics-based THz system where it is possible to switch it with minor modifications for THz spectroscopic studies and THz communication applications. Several bandwidth hungry applications that demands the use of THz spectrum for next generation communications is detailed. This includes the streaming of uncompressed HD/4K and beyond high-resolution videos, where the THz spectrum can be beneficial. Next, the motivation of using long THz fibers is discussed and we convince the readers that the THz fibers are not meant to replace the fibers in the optical-infrared region but to increase the reliability of THz wireless links. Particularly, the THz fibers can be used to provide connectivity in complex geometrical environments, secure communications and signal delivery to hard-to-reach areas. Several novel fiber/waveguide designs along with their fabrication technologies from the literature are presented. We then show that a simple solid core dielectric subwavelength fiber can be used to transmit the information in the order of several Gbps to a distance of a few meters

Microwave Photonic Applications - From Chip Level to System Level

Die Vermischung von Mikrowellen- und optischen Technologien – Mikrowellenphotonik – ist ein neu aufkommendes Feld mit hohem Potential. Durch die Nutzung der Vorzüge beider Welten hat die Mikrowellenphotonik viele Anwendungsfälle und ist gerade erst am Beginn ihrer Erfolgsgeschichte. Der Weg für neue Konzepte, neue Komponenten und neue Anwendungen wird dadurch geebnet, dass ein höherer Grad an Integration sowie neue Technologien wie Silicon Photonics verfügbar sind. In diesem Werk werden zuerst die notwendigen grundlegenden Basiskomponenten – optische Quelle, elektro-optische Wandlung, Übertragungsmedium und opto-elektrische Wandlung – eingeführt. Mithilfe spezifischer Anwendungsbeispiele, die von Chipebene bis hin zur Systemebene reichen, wird der elektrooptische Codesign-Prozess veranschaulicht. Schließlich werden zukünftige Ausrichtungen wie die Unterstützung von elektrischen Trägern im Millimeterwellen- und THz-Bereich sowie Realisierungsoptionen in integrierter Optik und Nanophotonik diskutiert.The hybridization between microwave and optical technologies – microwave photonics – is an emerging field with high potential. Benefitting from the best of both worlds, microwave photonics has many use cases and is just at the beginning of its success story. The availability of a higher degree of integration and new technologies such as silicon photonics paves the way for new concepts, new components and new applications. In this work, first, the necessary basic building blocks – optical source, electro-optical conversion, transmission medium and opto-electrical conversion – are introduced. With the help of specific application examples ranging from chip level to system level, the electro-optical co-design process for microwave photonic systems is illustrated. Finally, future directions such as the support of electrical carriers in the millimeter wave and THz range and realization options in integrated optics and nanophotonics are discussed

Scaling Optical Phased Arrays

Optical phased array (OPA) technology can improve the useful capabilities of lasers by controlling the relative optical phase of an array of emitting apertures. Combining lasers in this way can produce a beam with increased optical intensity, rapid beam pointing and the potential to perform adaptive optics to correct for atmospheric turbulence. Future applications of optical phased arrays, particularly ground-to-space laser transmission, require both the ability to combine individual high power optical sources and emitter counts greater than in existing implementations. Breakthrough Starshot proposes the ambitious goal of accelerating a light sail to 20% of the speed of light to reach the nearest solar system within a human lifespan, which may require upwards of 100 GW total power from 100 million emitters in a ground-to-space array. At a reduced scale, improved tracking and eventual manoeuvring of orbital space debris could be also improved through the use of a ground-to-space OPA. The research in this thesis presents improvements and techniques for internally-sensed optical phased array designs to allow the scaling to greater numbers of combined optical sources. While primarily motivated by enabling large scale ground-to-space optical phased arrays, consideration is given to more conventional systems and benefits to non-optical phased array applications. A thorough investigation of the limits of digitally enhanced heterodyne interferometry (DEHI), a technique which allows the simultaneous measure of multiple optical phase signals, forms the first major component of this work. In addition to optical phased arrays, this technique has potential applications in acoustic sensing, wavefront sensing, satellite interferometry and fibre frequency references. A combination of analytical, simulation and experimental work was performed to better predict crosstalk between optical phase measurements and establish a set of robust parameters to improve phase measurement performance. Recommendations for requirement dependent parameter choices when using this technique are presented. The optical phased array underpinning this work is internally sensed, implying the ability to measure differential emitter paths without the need for external beam sampling. However, a lingering challenge in previous implementations arose from the double-pass of internal optical pathlengths, resulting in a pi-phase ambiguity in the sensing. The second key challenge addressed in this thesis is a proof-of-concept experimental solution to resolve this ambiguity, demonstrated with a novel waveguide optical head created using three-dimensional laser inscription. In culmination, this research presents a conceptual design for a ground-to-space optical phased array to act as the "photon engine" component of the Breakthrough Starshot program. This design involves a system to interferometrically link multiple sub-arrays in a scalable hierarchy. The active control of differential pathlengths in the hierarchy are enabled using a combination of wavelength division multiplexing and DEHI. Internal array measurements in this design are partnered with measurements of a satellite mounted laser beacon for atmospheric phase sensing and to account for unevenness of the array surface across a kilometre scale. The satellite laser beacon is designed to operate at a different wavelength from the arrays outgoing beam, allowing weak beacon light to be distinguished from high powered emitter scattering. An associated technique established and modelled in this work is how phase measurements can be accurately mapped between wavelengths. Multiple variations of the complete array are modelled to assess fundamental performance limits of the sensing system with realistic system parameters for the combination of 100 million emitters

Recent Progress in Optical Fiber Research

This book presents a comprehensive account of the recent progress in optical fiber research. It consists of four sections with 20 chapters covering the topics of nonlinear and polarisation effects in optical fibers, photonic crystal fibers and new applications for optical fibers. Section 1 reviews nonlinear effects in optical fibers in terms of theoretical analysis, experiments and applications. Section 2 presents polarization mode dispersion, chromatic dispersion and polarization dependent losses in optical fibers, fiber birefringence effects and spun fibers. Section 3 and 4 cover the topics of photonic crystal fibers and a new trend of optical fiber applications. Edited by three scientists with wide knowledge and experience in the field of fiber optics and photonics, the book brings together leading academics and practitioners in a comprehensive and incisive treatment of the subject. This is an essential point of reference for researchers working and teaching in optical fiber technologies, and for industrial users who need to be aware of current developments in optical fiber research areas

The Impact of a Nuclear Disturbance on a Space-Based Quantum Network

Quantum communications tap into the potential of quantum mechanics to go beyond the limitations of classical communications. Currently, the greatest challenge facing quantum networks is the limited transmission range of encoded quantum information. Space-based quantum networks offer a means to overcome this limitation, however the performance of such a network operating in harsh conditions is unknown. This dissertation analyzes the capabilities of a space-based quantum network operating in a nuclear disturbed environment. First, performance during normal operating conditions is presented using Gaussian beam modeling and atmospheric modeling to establish a baseline to compare against a perturbed environment. Then, the DEfense Land Fallout Interpretive Code software and computational fluid dynamics study the effect of a nuclear explosion on the surrounding environment. Finally, these sources of noise are combined to estimate the degradation of quantum states being transmitted through a nuclear disturbed environment. It is found that the effects of a nuclear environment on a quantum network is a function of the height of blast, the explosive yield, and the network design. Debris lofted into the atmosphere during a surface blast dissipate after a couple of hours, yet the concentration is initially high and results in heavy signal loss. The nuclear fireball produced additional background light interference that scatters into the receiver\u27s detector from tens of seconds to a couple of minutes, causing excessive noise in the detector. All these effects are likely to impede a quantum network’s ability to distribute quantum information between a ground station and low Earth orbit satellite for approximately one transmission period. Afterwards, by the next satellite pass, normal operation is expected to resume. These results provide the operational capabilities of space-based optical quantum networks following a nuclear explosion. The model can be expanded to model satellite-based quantum networks in other harsh atmospheric environments