Download or read book Optical Orthogonal Frequency Division Systems with Direct Detection Receivers written by Juan Miguel Pérez Rosas and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: [ANGLÈS] The new generation of Pasive Optical Networks (PONs) to cover the last-mile to the user, is today a hot topic of research. Stringent performance requirements are both capacity and reach; these, together with reduced cost lead to consideration of a new paradigm. In this context, Optical OFDM (O-OFDM) is regarded as a promising candidate. From the many architectures being proposed for O-OFDM, the use of Direct Detection is particularly interesting for the downlink of Passive Optical Networks as cost-efficient Optical Network Units (ONUs) are required. In this line, this work encompasses a general study of Direct Detection Optical OFDM (DD O-OFDM) communications systems with emphasis on applications to optical Access Networks. It proposes designs for the downstream links of three different access network topologies differentiated by the optical modulation used: an Intensity Modulation (IM) with a Directly Modulated Laser (DML) an IM with a Mach-Zehnder Modulator (MZM) and an Amplitude modulation also with a MZM. All systems are based on Direct Detection receivers and the transmission of O-OFDM signals. The architectures, establish a wavelength agnostic link by transmitting Double Side Band signals. The impairments of a DSB transmission are studied and parting from them an optimization on the network?s parameters of frequency Guard Band and Carrier to Signal Power Ratio is performed. In order to test the architectures and optimize the parameters, simulations were executed using the commercial software VPI Transmission Maker TM. The testing of the architectures was done by minimizing receiver sensitivity at a BER 10-3 for data rates of 10Gbps and 40Gbps using 4-QAM and 16-QAM respectively, as digital modulation formats. Results show that spectral occupancy of the O-OFDM signal and the CSPR can be optimized while at the same time compensating for DSB impairments such as amplitude fading. Also the advantages and disadvantages of each optical modulation format depending on data rates and link?s distances required as well as cost-effectiveness are tested and described.

Download or read book Orthogonal Frequency division Multiplexing for Optical Communications written by Daniel Jose Fernandes Barros and published by Stanford University. This book was released on 2011 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: The drive towards higher spectral efficiency and maximum power efficiency in optical systems has generated renewed interest in the optimization of optical transceivers. In this work, we study the different optical applications: Wide Area Networks (WANs), Metropolitan Area Networks (MANs), Local Area Networks (LANs) and Personal Area Networks (PANs). In WANs or long-haul systems, orthogonal frequency-division multiplexing (OFDM) can compensate for linear distortions, such as group-velocity dispersion (GVD) and polarization-mode dispersion (PMD), provided the cyclic prefix is sufficiently long. Typically, GVD is dominant, as it requires a longer cyclic prefix. Assuming coherent detection, we show how to analytically compute the minimum number of subcarriers and cyclic prefix length required to achieve a specified power penalty, trading off power penalties from the cyclic prefix and from residual inter-symbol interference (ISI) and inter-carrier interference (ICI). We derive an analytical expression for the power penalty from residual ISI and ICI. We also show that when nonlinear effects are present in the fiber, single-carrier with digital equalization outperforms OFDM for various dispersion maps. We also study the impairments of electrical to optical conversion when using Mach-Zehnder (MZ) modulators. OFDM has a high peak-to-average ratio (PAR), which can result in low optical power efficiency when modulated through a Mach-Zehnder (MZ) modulator. In addition, the nonlinear characteristic of the MZ can cause significant distortion on the OFDM signal, leading to in-band intermodulation products between subcarriers. We show that a quadrature MZ with digital pre-distortion and hard clipping is able to overcome the previous impairments. We consider quantization noise and compute the minimum number of bits required in the digital-to-analog converter (D/A). Finally, we discuss a dual-drive MZ as a simpler alternative for the OFDM modulator, but our results show that it requires a higher oversampling ratio to achieve the same performance as the quadrature MZ. In MANs, we discuss the use OFDM for combating GVD effects in amplified direct-detection (DD) systems using single-mode fiber. We review known direct-detection OFDM techniques, including asymmetrically clipped optical OFDM (ACO-OFDM), DC-clipped OFDM (DC-OFDM) and single-sideband OFDM (SSB-OFDM), and derive a linearized channel model for each technique. We present an iterative procedure to achieve optimum power allocation for each OFDM technique, since there is no closed-form solution for amplified DD systems. For each technique, we minimize the optical power required to transmit at a given bit rate and normalized GVD by iteratively adjusting the bias and optimizing the power allocation among the subcarriers. We verify that SSB-OFDM has the best optical power efficiency among the different OFDM techniques. We compare these OFDM techniques to on-off keying (OOK) with maximum-likelihood sequence detection (MLSD) and show that SSB-OFDM can achieve the same optical power efficiency as OOK with MLSD, but at the cost of requiring twice the electrical bandwidth and also a complex quadrature modulator. We compare the computational complexity of the different techniques and show that SSB-OFDM requires fewer operations per bit than OOK with MLSD. In LANs, we compare the performance of several OFDM schemes to that of OOK in combating modal dispersion in multimode fiber links. We review known OFDM techniques using intensity modulation with direct detection (IM/DD), including DC-OFDM, ACO-OFDM and pulse-amplitude modulated discrete multitone (PAM-DMT). We describe an iterative procedure to achieve optimal power allocation for DC-OFDM, and compare analytically the performance of ACO-OFDM and PAM-DMT. We also consider unipolar M-ary pulse-amplitude modulation (M-PAM) with minimum mean-square error decision-feedback equalization (MMSE-DFE). For each technique, we quantify the optical power required to transmit at a given bit rate in a variety of multimode fibers. For a given symbol rate, we find that unipolar M-PAM with MMSE-DFE has a better power performance than all OFDM formats. Furthermore, we observe that the difference in performance between M-PAM and OFDM increases as the spectral efficiency increases. We also find that at a spectral efficiency of 1 bit/symbol, OOK performs better than ACO-OFDM using a symbol rate twice that of OOK. At higher spectral efficiencies, M-PAM performs only slightly better than ACO-OFDM using twice the symbol rate, but requires less electrical bandwidth and can employ analog-to-digital converters at a speed only 81% of that required for ACO-OFDM. In PANs, we evaluate the performance of the three IM/DD OFDM schemes in combating multipath distortion in indoor optical wireless links, comparing them to unipolar M-PAM with MMSE-DFE. For each modulation method, we quantify the received electrical SNR required at a given bit rate on a given channel, considering an ensemble of 170 indoor wireless channels. When using the same symbol rate for all modulation methods, M-PAM with MMSE-DFE has better performance than any OFDM format over a range of spectral efficiencies, with the advantage of M-PAM increasing at high spectral efficiency. ACO-OFDM and PAM-DMT have practically identical performance at any spectral efficiency. They are the best OFDM formats at low spectral efficiency, whereas DC-OFDM is best at high spectral efficiency. When ACO-OFDM or PAM-DMT are allowed to use twice the symbol rate of M-PAM, these OFDM formats have better performance than M-PAM. When channel state information is unavailable at the transmitter, however, M-PAM significantly outperforms all OFDM formats. When using the same symbol rate for all modulation methods, M-PAM requires approximately three times more computational complexity per processor than all OFDM formats and 63% faster analog-to-digital converters, assuming oversampling ratios of 1.23 and 2 for ACO-OFDM and M-PAM, respectively. When OFDM uses twice the symbol rate of M-PAM, OFDM requires 23% faster analog-to-digital converters than M-PAM but OFDM requires approximately 40% less computational complexity than M-PAM per processor.

Download or read book OFDM Systems for Optical Communication with Intensity Modulation and Direct Detection written by Jian Dang and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Intensity modulation and direct detection (IM/DD) is a cost-effective optical communication strategy which finds wide applications in fiber communication, free-space optical communication, and indoor visible light communication. In IM/DD, orthogonal frequency division multiplexing (OFDM), originally employed in radio frequency communication, is considered as a strong candidate solution to combat with channel distortions. In this research, we investigate various potential OFDM forms that are suitable for IM/DD channel. We will elaborate the design principles of different OFDM transmitters and investigate different types of receivers including the proposed iterative receiver. In addition, we will analyze the spectral efficiency and decoding complexities of different OFDM systems to give a whole picture of their performance. Finally, simulation results are given to assess the detection performance of different receivers.

Download or read book Optical Fiber and Wireless Communications written by Rastislav Róka and published by BoD – Books on Demand. This book was released on 2017-06-21 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book Optical Fiber and Wireless Communications provides a platform for practicing researchers, academics, PhD students, and other scientists to review, plan, design, analyze, evaluate, intend, process, and implement diversiform issues of optical fiber and wireless systems and networks, optical technology components, optical signal processing, and security. The 17 chapters of the book demonstrate capabilities and potentialities of optical communication to solve scientific and engineering problems with varied degrees of complexity.

Download or read book Orthogonal Frequency Division Multiplexing in Optical Communication Systems written by Dr. Ashad Ullah Qureshi and published by Concepts Books Publication. This book was released on 2022-06-01 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optical fiber communication has emerged as a high potential substitute for communication methods such as twisted pair and coaxial wire. The main advantage of optical fiber over previous methods is to have higher capacity of data rate transmission. The conventional types of modulation and demodulation technique, which have been used through optical fiber communication system are Wavelength Division Multiplexing (WDM) technique and Dense Wavelength Division Multiplexing (DWDM) technique so far.

Download or read book AI and IoT Based Intelligent Automation in Robotics written by Ashutosh Kumar Dubey and published by John Wiley & Sons. This book was released on 2021-04-13 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 24 chapters in this book provides a deep overview of robotics and the application of AI and IoT in robotics. It contains the exploration of AI and IoT based intelligent automation in robotics. The various algorithms and frameworks for robotics based on AI and IoT are presented, analyzed, and discussed. This book also provides insights on application of robotics in education, healthcare, defense and many other fields which utilize IoT and AI. It also introduces the idea of smart cities using robotics.

Download or read book Enabling Technologies for High Spectral efficiency Coherent Optical Communication Networks written by Xiang Zhou and published by John Wiley & Sons. This book was released on 2016-04-29 with total page 719 pages. Available in PDF, EPUB and Kindle. Book excerpt: Enabling Technologies for High Spectral-efficiency Coherent Optical Communication Networks Presents the technological advancements that enable high spectral-efficiency and high-capacity fiber-optic communication systems and networks This book examines key technology advances in high spectral-efficiency fiber-optic communication systems and networks, enabled by the use of coherent detection and digital signal processing (DSP). The first of this book’s 16 chapters is a detailed introduction. Chapter 2 reviews the modulation formats, while Chapter 3 focuses on detection and error correction technologies for coherent optical communication systems. Chapters 4 and 5 are devoted to Nyquist-WDM and orthogonal frequency-division multiplexing (OFDM). In chapter 6, polarization and nonlinear impairments in coherent optical communication systems are discussed. The fiber nonlinear effects in a non-dispersion-managed system are covered in chapter 7. Chapter 8 describes linear impairment equalization and Chapter 9 discusses various nonlinear mitigation techniques. Signal synchronization is covered in Chapters 10 and 11. Chapter 12 describes the main constraints put on the DSP algorithms by the hardware structure. Chapter 13 addresses the fundamental concepts and recent progress of photonic integration. Optical performance monitoring and elastic optical network technology are the subjects of Chapters 14 and 15. Finally, Chapter 16 discusses spatial-division multiplexing and MIMO processing technology, a potential solution to solve the capacity limit of single-mode fibers. Contains basic theories and up-to-date technology advancements in each chapter Describes how capacity-approaching coding schemes based on low-density parity check (LDPC) and spatially coupled LDPC codes can be constructed by combining iterative demodulation and decoding Demonstrates that fiber nonlinearities can be accurately described by some analytical models, such as GN-EGN model Presents impairment equalization and mitigation techniques Enabling Technologies for High Spectral-efficiency Coherent Optical Communication Networks is a reference for researchers, engineers, and graduate students.

Download or read book Introduction to OFDM Receiver Design and Simulation written by Y.J. Liu and published by Artech House. This book was released on 2019-11-30 with total page 273 pages. Available in PDF, EPUB and Kindle. Book excerpt: This practical book is an accessible introduction to Orthogonal frequency-division multiplexing (OFDM) receiver design, a technology that allows digitized data to be carried by multiple carriers. It offers a detailed simulation study of an OFDM algorithm for Wi-Fi and 4G cellular that can be used to understand other OFDM waveforms. Extensive simulation studies are included using the transmissionwaveform given by the IEEE 802.11 standard. Scrambler, error-correcting codes, interleaver and radio-wave propagation model are included. OFDM waveform characteristics, signal acquisition, synchronization issues, channel estimation and tracking, hard and soft decision decoding are all covered. Detailed derivations leading to the final formula for any algorithm are given, which allows the reader to clearly understand the approximations and conditions behind the formulas and apply them appropriately. The algorithms are selected not just for the best performance from simulation study but also for easy implementation. An example is a unique algorithm for signal acquisition using the principle of maximum likelihood detection.

Download or read book The Effect of Laser Noise on an Optical Orthogonal Frequency Division Multiplexing OFDM System written by Zuraidah Zan and published by . This book was released on 2013 with total page 588 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years, researchers and network equipment manufacturers have focused on the development of a 100 Gb/s optical transmission systems to cater the ever increasing demands for bandwidth. To cater the demands, optical orthogonal frequency division multiplexing (O-OFDM) has been proposed. O-OFDM has been shown as a promising technique to increase spectral efficiency with its ability to compensate for chromatic and polarisation mode dispersion. There are two forms of receiver used for long haul O-OFDM links: coherent-OOFDM (CO-OFDM) and direct detection O-OFDM (DDO-OFDM). The CO-OFDM system is known to be limited by the laser's phase noise, where the system requires a narrow linewidth laser at both transmitter and receiver, where these lasers phase must track one-another. In the DDO-OFDM system, an optical carrier is transmitted along with the subcarriers so both originate from the same laser, and both experience the same degradations along the fibre. Thus, the linewidth, or equivalently phase-noise, requirements are far less stringent than for CO-OFDM systems. However, given that laser phase noise will be converted to intensity noise (PM-to-IM conversion noise) along a dispersive fibre, there will be some effect on performance in a DDO-OFDM system. The question is whether this is significant, given that the fibre dispersion is not optically compensated as in conventional lightwave systems.In this thesis, laser phase noise effect upon detection in a DDO-OFDM system is shown to impose broad noise pedestal around a subcarrier for higher frequency subcarriers when there is a high accumulated dispersion. The noise pedestal can introduce inter-subcarrier-interference between the adjacent subcarriers. This is different in a CO-OFDM system, where the phase noise is independent of the subcarriers' frequency and common to all subcarriers. This thesis focuses on the DDO-OFDM system using external modulation at the transmitter. A transmission system was developed to study the effects of the laser relative intensity noise (RIN) and phase noise over a long-haul transmission, and to show the importance of the laser's characteristics. Experimental measurements on a commercial fixed-wavelength distributed feedback (DFB) laser investigated its RIN, linewidth and light vs. current (L-I) characteristics. The effect of external modulation of this laser was investigated. With the externally-modulated transmitter, the laser chirp is ignored. The linewidth measurement was done using self-homodyne technique and validated using a high-resolution spectrophotometer. The measurements showed inter-dependency between the linewidth and RIN, which agreed with theory. A laser linewidth emulator was developed and demonstrated experimentally. This was done by phase modulating a semiconductor's laser output to broaden its linewidth. With this laser, the linewidth can be made independent from the other laser's noise characteristics. Simulations and experiments were performed to study the interaction of linewidth and fibre dispersion. The interaction produces noise conversion from phase modulation to intensity modulation, where the noise PSD was obtained. An analytical equation of the PM-to-IM's upper-bound was derived and plotted on the noise PSD's amplitude. When the laser was modulated with RF tones, a noise pedestal around each of the tones was obtained. The peak power of the noise is shown to increase with the increased of the tone's frequency. This is due to the phase walk-off of the high frequency subcarrier from the carrier is larger than the low frequency subcarrier. The peak also increases when a wider linewidth was used. This noise was shown to cause phase rotations of the received symbols and reduces the Q performance of the DDO-OFDM system. To reduce the effect of the linewidth in the DDO-OFDM system, an experiment using a simple delay line to match the delay experienced by the subcarrier was performed. The result shows improvement of the subcarriers' Q performance. Finally, this thesis also presented the performance of the DDO-OFDM system in transmitting high-speed data of 120 Gbit/s. This experiment involved several important device improvements in order to achieve a good quality and wide RF-signal bandwidth. In this transmission, a variant of the DDO-OFDM system employing self-coherent polarization-diversity receiver design was developed.

Download or read book OFDM for Optical Communications written by William Shieh and published by Academic Press. This book was released on 2009-09-18 with total page 457 pages. Available in PDF, EPUB and Kindle. Book excerpt: - The first book on optical OFDM by the leading pioneers in the field - The only book to cover error correction codes for optical OFDM - Gives applications of OFDM to free-space communications, optical access networks, and metro and log haul transports show optical OFDM can be implemented - Contains introductions to signal processing for optical engineers and optical communication fundamentals for wireless engineers This book gives a coherent and comprehensive introduction to the fundamentals of OFDM signal processing, with a distinctive focus on its broad range of applications. It evaluates the architecture, design and performance of a number of OFDM variations, discusses coded OFDM, and gives a detailed study of error correction codes for access networks, 100 Gb/s Ethernet and future optical networks. The emerging applications of optical OFDM, including single-mode fiber transmission, multimode fiber transmission, free space optical systems, and optical access networks are examined, with particular attention paid to passive optical networks, radio-over-fiber, WiMAX and UWB communications. Written by two of the leading contributors to the field, this book will be a unique reference for optical communications engineers and scientists. Students, technical managers and telecom executives seeking to understand this new technology for future-generation optical networks will find the book invaluable. William Shieh is an associate professor and reader in the electrical and electronic engineering department, The University of Melbourne, Australia. He received his M.S. degree in electrical engineering and Ph.D. degree in physics both from University of Southern California. Ivan Djordjevic is an Assistant Professor of Electrical and Computer Engineering at the University of Arizona, Tucson, where he directs the Optical Communications Systems Laboratory (OCSL). His current research interests include optical networks, error control coding, constrained coding, coded modulation, turbo equalization, OFDM applications, and quantum error correction. "This wonderful book is the first one to address the rapidly emerging optical OFDM field. Written by two leading researchers in the field, the book is structured to comprehensively cover any optical OFDM aspect one could possibly think of, from the most fundamental to the most specialized. The book adopts a coherent line of presentation, while striking a thoughtful balance between the various topics, gradually developing the optical-physics and communication-theoretic concepts required for deep comprehension of the topic, eventually treating the multiple optical OFDM methods, variations and applications. In my view this book will remain relevant for many years to come, and will be increasingly accessed by graduate students, accomplished researchers as well as telecommunication engineers and managers keen to attain a perspective on the emerging role of OFDM in the evolution of photonic networks." -- Prof. Moshe Nazarathy, EE Dept., Technion, Israel Institute of Technology - The first book on optical OFDM by the leading pioneers in the field - The only book to cover error correction codes for optical OFDM - Applications of OFDM to free-space communications, optical access networks, and metro and log haul transports show optical OFDM can be implemented - An introduction to signal processing for optical communications - An introduction to optical communication fundamentals for the wireless engineer

Download or read book Investigation of Receiver Concepts for Coherent Optical Orthogonal Frequency Division Multiplexing Communication Systems written by Kidsanapong Puntsri and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book OFDM Based RF and Optical Wireless Systems written by Bilal Ranjha and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Orthogonal frequency division multiplexing (OFDM) is currently being used predominantly in radio frequency (RF) mobile broadband communication systems because of its ability to combat inter-symbol interference (ISI) and robustness against frequency selective fading caused by multipath wireless channel. Wireless mobile standards like 3G and 4G long term evolution (LTE) use orthogonal frequency division multiple access (OFDMA) as a multiplexing/modulation scheme. Despite its many advantages like single tap frequency domain equalization and fast discrete time implementation, OFDM suffers from certain disadvantages like high peak-to-average power ratio (PAPR) and high sensitivity to carrier frequency offset (CFO). Although OFDM has solved problems like multipath fading but it cannot solve the emerging problems like scarcity of RF spectrum for mobile wireless broadband applications. Optical wireless (OW) communication has recently gained a lot of attention as a candidate to complement RF communication. It offers advantages like virtually infinite bandwidth, data security and use of low cost transmitters and receivers like solid state light emitting diodes (LEDs) and optical detectors. OFDM is also being considered as a candidate for visible light communication (VLC) as it offers robustness against multipath caused by diffuse indoor OW channel. One way to realize VLC is intensity modulation direct detection (IM/DD). Although the major difference between RF and OW based OFDM lies in the front end of transmitter and receiver, but due to the unipolar nature of optical intensity in IM/DD system, methods of generating baseband OFDM signal, techniques to reduce PAPR and timing synchronization schemes for RF cannot be directly applied to optical OFDM systems and therefore must be revisited. Therefore, in this thesis, we will first look into the interference caused by CFO in RF based OFDMA system and will analyze the characteristics of this interference for two mapping subcarrier strategies. We will explicitly calculate SINR expression for OFDMA based systems and analyze two types of symbol mapping strategies and characterize interferences due to CFO for each scheme. We will also develop some techniques to reduce high PAPR in OFDM based OW systems since the non-linear characteristics of LED transmitters can severely affect system performance. We will look into various precoding based PAPR reduction techniques. We will then analyze performance of various OFDM based OW schemes in multipath diffuse indoor wireless channel. We will compare performance of conventional schemes with a precoded version. We will then describe in detail our newly proposed power and spectrally efficient hybrid asymmetrically clipped optical orthogonal frequency division multiplexing (HACO-OFDM) system and compare its performance with previously proposed schemes. Finally, we will present details of our newly proposed timing synchronization scheme for power efficient asymmetrically clipped (AC) OW OFDM systems. Detailed performance analysis will be presented and a comparison will be developed. Simulation results show that our proposed scheme outperforms all other timing synchronization techniques and exhibits perfect accuracy even at very low signal-to-noise ratio (SNR). Besides performance, our scheme works perfectly for multiple AC OW which proves its high versatility.

Download or read book Phase Modulated Optical Communication Systems written by Keang-Po Ho and published by Springer Science & Business Media. This book was released on 2005-12-06 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fiber-optic communication systems have revolutionized our telecommunication infrastructures – currently, almost all telephone land-line, cellular, and internet communications must travel via some form of optical fibers. In these transmission systems, neither the phase nor frequency of the optical signal carries information – only the intensity of the signal is used. To transmit more information in a single optical carrier, the phase of the optical carrier must be explored. As a result, there is renewed interest in phase-modulated optical communications, mainly in direct-detection DPSK signals for long-haul optical communication systems. When optical amplifiers are used to maintain certain signal level among the fiber link, the system is limited by amplifier noises and fiber nonlinearities. Phase-Modulated Optical Communication Systems surveys this newly popular area, covering the following topics: - The transmitter and receiver for phase-modulated coherent lightwave systems - Method for performance analysis of phase-modulated optical signals - Direct-detection DPSK signal with fiber nonlinearities, degraded by nonlinear phase noise and intrachannel effects - Wavelength-division-multiplexed direct-detection DPSK signals - Multi-level phase-modulated optical signals, such as the four-phase DQPSK signal. Graduate students, professional engineers, and researchers will all benefit from this updated treatment of an important topic in the optical communications field.

Download or read book Digital Optical Communications written by Le Nguyen Binh and published by CRC Press. This book was released on 2008-11-20 with total page 610 pages. Available in PDF, EPUB and Kindle. Book excerpt: The need for advanced transmission techniques over long haul optically amplified communications has prompted a convergence of digital and optical communications. Digital Optical Communications explores the practical applications of this union and applies digital modulation techniques to optical communications systems.After reviewing the fundamental

Download or read book Optical Modulation written by Le Nguyen Binh and published by CRC Press. This book was released on 2017-11-22 with total page 849 pages. Available in PDF, EPUB and Kindle. Book excerpt: This books aims to present fundamental aspects of optical communication techniques and advanced modulation techniques and extensive applications of optical communications systems and networks employing single-mode optical fibers as the transmission system. New digital techqniues such as chromatic dispersion, polarization mode dispersion, nonlinear phase distortion effects, etc. will be discussed. Practical models for practice and understanding the behavior and dynamics of the devices and systems will be included.

Download or read book Investigation on High Spectral Efficiency Coherent Optical OFDM Transmission Systems written by Hussin Saleh Ibrahim Saied Saleh and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Orthogonal frequency division multiplexing (OFDM) belongs to multicarrier technology which is used in many broadband wired and wireless communication systems. It is used to combat multipath fading. Although, OFDM systems are complex compared to single carrier systems due to design of their transmitter and receiver and also the associated signal processing, significant benefits are achieved. Optical OFDM systems can be classified into three approaches according to the detection scheme. The approaches are direct detection optical OFDM (DDO-OFDM), coherent optical OFDM (CO-OFDM) and self coherent optical OFDM (SCO-OFDM). The most important drawbacks of CO-OFDM are the high peak-to-average power ratio (PAPR), high sensitivity to frequency offset and phase noise. The present dissertation introduces the performance of different pulse shaping techniques. Furthermore, it presents new algorithms to reduce the phase noise effects and compares the system performance with different existing algorithms. Moreover, the performance of a new system design is investigated. The provided dissertation includes four original contributions.Initially, the theoretical principles of OFDM are presented with detailing on the advantages and disadvantages of OFDM compared to the single carrier modulation technology. The theoretical fundamentals of optical OFDM and the differences between the three systems are followed. Furthermore, performance of the three existing optical OFDM systems are elaborated and compared. A square root raised-cosine pulse shaping of OFDM symbols is suggested to enhance the efficiency of CO-OFDM systems. Next, the different kinds of the phase noise effects on the OFDM signals are defined and the impact of the laser and nonlinear phase noise is reported. Different existing phase noise compensation algorithms are presented. Moreover, the modified and new phase noise compensation schemes are provided and compared. ; eng

Download or read book Noises in Optical Communications and Photonic Systems written by Le Nguyen Binh and published by CRC Press. This book was released on 2016-11-17 with total page 474 pages. Available in PDF, EPUB and Kindle. Book excerpt: Transmitting information over optical fibers requires a high degree of signal integrity due to noise levels existing in optical systems. Proper methods and techniques for noise evaluations are critical in achieving high-performance. This book provides a fundamental understanding of noise generation processes in optical communications and photonic signals. It discusses techniques for noise evaluation in optical communication systems, especially digital optical systems, as well as transmission systems performance and noise impacts in photonic processing systems