Optical Fiber Communications

Optical burst switching (OBS) is one promising method for data transfer in photonic networks based on a WDM (Wavelength Division Multiplexing) technology. In the OBS scheme, the wavelength is exclusively reserved along the source and destination nodes, when the burst data is generated at the source. Then, efficient data transfer is expected. However, its performance is heavily dependent on the number of links that the lightpath goes through. TCP-based applications account for a majority of data traffic in the Internet; thus understanding and improving the performance of TCP over OBS networks is critical. In this paper, we present a new parallel wavelength reservation method for optical burst switching (OBS) networks based on adapting the set of potential wavelengths with the number of hops in the path. The uniqueness of this work when compared to existing works is that buffering resources, which consist of Optical Delay Lines (ODLs), are considered in the reservation mechanism. The consequence of this is that the time made by the segments in the various buffers across the selected path is taken into consideration. Various simulation experiments have been conducted to evaluate the performance of the scheme. It is found that our approach has better performance than previous related works reported in the literature.

Two twelve-channel arrays based on surface-etched slot gratings, one with nonuniformly spaced slots and another with uniformly spaced slots are presented for laser operation in the O-band. A wavelength tuning range greater than 40 nm, with a side-mode suppression ratio (SMSR) > 40 dB over much of this range and output power greater than 20 mW, was obtained for the array with non-uniform slots over a temperature range of 15°C-60°C. The introduction of multiple slot periods, chosen such that there is minimal overlap among the side reflection peaks, is employed to suppress modes lasing one free spectral range (FSR) from the intended wavelength. The tuning range of the array with uniformly spaced slots, on the other hand, was found to be discontinuous due to mode-hopping to modes one FSR away from the intended lasing mode which are not adequately suppressed. Spectral linewidth was found to vary across devices with the lowest measured linewidths in the range of 2 MHz to 4 MHz.

The optical wireless communication systems are rapidly gaining popularity as effective means of transferring data at high rates over short distances. These systems facilitate rapidly deployable, lightweight, high-capacity communication without licensing fees and tariffs. On the other hand, the performance of this new technology depends strongly on the atmospheric conditions and the parameters of the link such as the length and the operation wavelength. In this work, we extract closed form mathematical expression for the evaluation of the average (ergodic) capacity of such a system, using the log-normal and gamma-gamma distribution, in order to model the atmospheric turbulence conditions and we study the influence of the above parameters on it.

Advanced modulation formats can enable >40 Gb/s data rates in waveguide-based optical interconnects without the need for high-specification optoelectronic components. Record 56Gb/s PAM-4 data transmission is demonstrated over a 1 m-long multimode polymer waveguide.

Burst contention is a well-known challenging problem in Optical Burst Switching (OBS) networks. Deflection routing is used to resolve contention. Burst retransmission is used to reduce the Burst Loss Ratio (BLR) by retransmitting dropped bursts. Previous works show that combining deflection and retransmission outperforms both pure deflection and pure retransmission approaches. This paper proposes a new Adaptive Hybrid Deflection and Retransmission (AHDR) approach that dynamically combines deflection and retransmission approaches based on network conditions such as BLR and link utilization. Network Simulator 2 (ns-2) is used to simulate the proposed approach on different network topologies. Simulation results show that the proposed approach outperforms static approaches in terms of BLR by using an adaptive decision threshold.

Network and Internet applications are growing very fast since the need to secure these applications are very fast. For this purpose cryptography algorithms (symmetric & Asymmetric) are proposed. The use of relevant algorithm deals with the level of data safety in the cloud because data security in cloud computing is a serious issue as the data centres are located worldwide. Authentication is the most essential procedure to ensure cloud data in a secured manner. However, strong user authentication is the main requirement for cloud computing that reduces the unauthorized user access of data on the cloud. Data security is a more important issue in cloud computing. Thus, the need to ensure the safety of the information that is exchanged between the users and the cloud became more significant. Many security and authentication techniques have been proposed to secure the exchanged data. These techniques aim to keep the authentication, privacy and reliability levels of data. Here in this survey paper, some algorithms in cloud computing are discussed.

Artur Dybko, Światłowodowy czujnik do pomiaru stężenia jonów hydroniowych, Praca dyplomowa magisterska, Instytut Podstaw Elektroniki, Politechnika Warszawska, 1990  (okładka, spis treści, dedykacja)
Wstęp,
Przegląd konstrukcji pH-metrów światłowodowych,
Wybór metody pomiarowyej,
Wyniki prac doświadczalnych,
Sugestie dalszych prac,
Dodatek chemiczny
Literatura.

An economical and viable option to
conventional and high rate materials is the use of
fiber glass/epoxy composites, but for impact
applications their toughness still has to be enhanced.
The toughness and additional mechanical properties
can be improved by using very small amount of PET
into an epoxy system. In the present work epoxy
modified by way of MMT Clay (3 wt % of Epoxy)
& PET fiber is manufactured using hand layup
system. The nano composites have been
characterized using Impact, Tensile, Bending and
Microhardness tests. The mechanical properties are
compared by means of those found for PET
introduced epoxy nano composites. The mechanical
test shows that the presence of 1 wt% PET fiber
largely increases impact strength and flexural
strength. Micro hardness decreased at PET fiber
loading.

The performance of optical communication system is mainly determined by the various modulation formats in L band at different bit rates. The study of optical communication systems is multidisciplinary involving a wide range of area including: optical communication design, channel modeling, communications and information theory. Optisystem software is employed for analyzing these conditions and simulation of optical communication using Multiplex and Demultiplex by comparing with Return-to-zero (RZ), Non-Return-to-zero (NRZ) modulation formats. It has been investigated that in L band the distance covered with more data rates in RZ formats gives better results as compared to with NRZ. The high quality factor is obtained in case of RZ format. For RZ format the BER is 1.3486e-009 at 25Gbps and Q value is 6.847 at 1610nm.

Optical fibers are utilized widely for data transmission systems because of their capacity to carry extensive information and dielectric nature. Network architectures utilizing multiple wavelengths per optical fiber are used in central, metropolitan, or broad‐area applications to link thousands of users with a vast range of transmission speeds and capacities. A powerful feature of an optical communication link is sending several wavelengths through the 1300‐to‐1600‐ nm range of a fibre simultaneously. The technology of integrating several wavelengths onto a similar fiber is called wavelength division multiplexing (WDM). The principle of WDM utilized in concurrence with optical amplifiers has an outcome in communication links that permit rapid communications among users in the world's countries. This paper presents an overview of the challenges of fibre optic communication. This paper offers an outline of the areas to be the most relevant for the future advancement of optical com...

Digital computers have evolved from adding machines and vacuum-tube computers. Early electronic calculators led to the initial development of microprocessors which have now progressed to multitasking high speed computers. The efficiency of the methods, techniques and algorithms to implement mathematical functions is a key factor for achieving higher speeds and accuracy in computations, and also efficient use of memory. Digital computers operate on integers as well as floating point numbers. Operations on floating-point values are more complex. Many times a balance between speed and accuracy, along with other factors like input/output ranges is to be achieved. In this paper various techniques and algorithms are studied and analysed for some important scientific functions used in calculators and computers.

This paper presents a review of the numerical methods for the analysis of the homogeneous and inhomogeneous, isotropic and anisotropic, microwave and optical dielectric waveguides with arbitrarily-shaped cross sections. The characteristics of various methods are compared, and a set of qualitative criteria to guide the selection of an appropriate method for a given problem is proposed. The main approaches discussed are those of point matching, integral equations, finite difference, and finite element.

This paper proposes a security architecture for optical code division multiple access networks based on lattice cryptography. Unlike existing approaches, which have mainly focused on optical components such as phase masks and delay lines, our cryptosystem encompasses a secure code construction process. In fact, given a set of optical orthogonal codewords, we associate a pair of bases (a public basis and a private basis) to every user and we show that the projection of a codeword on the public basis of the receiver and the addition of a random error enhances the confidentiality performance of the code. The proposed public key cryptosystem is based on lattice cryptography. The security of this scheme relies mainly on the complexity of the closest vector-problem in an integer lattice. We found that our technique performs better than the existing approaches in terms of robustness to cryptanalysis. We also study the security of our lattice cryptosystem with regard to the properties of the bases pairs and the error vectors.

Assessing the average energy intensity of Internet transmissions is a complex task that has been a controversial subject of discussion. Estimates published over the last decade diverge by up to four orders of magnitude — from 0.0064 kilowatt-hours per gigabyte (kWh/GB) to 136 kWh/GB. This article presents a review of the methodological approaches used so far in such assessments: i) top–down analyses based on estimates of the overall Internet energy consumption and the overall Internet traffic, whereby average energy intensity is calculated by dividing energy by traffic for a given period of time, ii) model-based approaches that model all components needed to sustain an amount of Internet traffic, and iii) bottom–up approaches based on case studies and generalization of the results. Our analysis of the existing studies shows that the large spread of results is mainly caused by two factors: a) the year of reference of the analysis, which has significant influence due to efficiency gains in electronic equipment, and b) whether end devices such as personal computers or servers are included within the system boundary or not. For an overall assessment of the energy needed to perform a specific task involving the Internet, it is necessary to account for the types of end devices needed for the task, while the energy needed for data transmission can be added based on a generic estimate of Internet energy intensity for a given year. Separating the Internet as a data transmission system from the end devices leads to more accurate models and to results that are more informative for decision makers, because end devices and the networking equipment of the Internet usually belong to different spheres of control.

1. Fiber Optik Sistemlerinin Gelişimi
1.1. Fiber Optik Haberleşme Sistemi
1.2. Fiber Optik Sinyal İletimini Etkileyen Faktörler
1.3. İletişimde Çoklama Teknikleri
2. Fiber Optik Amlifikatörler
3. Erbiyum Katkılı Fiber Yükselteçler
3.1 EKFY’nin Çalışma Şekli
4. Sonuç :

In 5G and beyond telecommunication infrastructures a crucial challenge in achieving the strict Key Performance Indicators (KPIs) regarding capacity, latency, and guaranteed quality of service, is the efficient handling of the fronthaul bottleneck. This part of the next generation networks is expected to comprise the New Radio (NR) access and the Next Generation Passive Optical Network (NGPON) domains. Latest developments load the fronthaul with computing tasks as well (e.g., for AI-based processes) in the context of Mobile Edge Computing (MEC). Towards efficient management of all resource types, this paper proposes a joint allocation scheme with three optimization phases for radio, optical, and MEC resources. This scheme, which has been developed in the context of the blueSPACE 5G Infrastructure Public Private Partnership (5G PPP) project, exploits cutting-edge technologies, such as radio beamforming, spatial-spectral granularity in optical networks, and Network Function Virtualization (NFV), to provide dynamic, adaptive, and energy efficient allocation of resources. The devised model is mathematically described and the overall solution is evaluated in a realistic simulation scenario, demonstrating its effectiveness.

Optical pulses with duration below 60 ps were generated by gain switching a Vertical Cavity Surface Emitting Laser (VCSEL) at 1535 nm. We used a radio frequency (RF) sinusoidal signal to modulate the device near threshold. Relaxation oscillations or pulse train generation were observed depending on the gain switching conditions. Repetition rates between 100 MHz and 2 GHz were tested. The dependence of the pulse width and amplitude was investigated in relation with the bias current and excitation frequency and amplitude. The optimal configuration of the current bias and RF modulating signal provided the shortest pulse duration of 57 ps at repetition rate of 800 MHz.

An 11Gb/s Equalizer is designed in 45nm CMOS to compensate for the losses in a 12" PCB trace. Amplitude variations are compensated with a limiting amplifier that provides a constant swing to a digital phase detector. An offset cancellation loop is used to attenuate offset in the high gain stage.

Speed is the essential part of communication system. It deals with the growth of the system, because in any system quick response is required in order to achieve the speed limit there are so many obstacle come in the path of telecommunication .Although Optical fiber plays the important role in the development of the system characteristics but also have some limitation like dispersion is on of them. While improving the sped of data transmission the dispersion will occur in the path of transmission which can be improve by using FBG (Fiber Bragg Grating). FBG is a key component in optical communication system as, dispersion compensators, filters and flatteners gain and improve Quality factor. Fiber Bragg Grating (FBG) as dispersion compensator. The analysis has been simulated in efficient optical communication software called optisystem. The performance of the FBG has been studied on the basis of input power, length of OFC, attenuation, line width, FBG grid size.

Parallel sorting algorithms order a set of elements USING MULTIPLE processors in order to enhance the performance of sequential sorting algorithms. In general, the performance of sorting algorithms are EVALUATED IN term of algorithm growth rate according to the input size. In this paper, the running time, parallel speedup and parallel efficiency OF PARALLEL bubble sort is evaluated and measured. Message Passing Interface (MPI) IS USED for implementing the parallel version of bubble sort and IMAN1 supercomputer is used to conduct the results. The evaluation results show that parallel bubble sort has better running time as the number of processors increases. On other hand, regarding parallel efficiency, parallel bubble sort algorithm is more efficient to be applied OVER SMALL number of processors.

Orthogonal frequency division multiplexing (OFDM) has proved to be a promising technique to increase the reach and bit rate both in long-haul communications and in passive optical networks. This paper, for the first time, investigates the use of OFDM combined with electrical CDMA in presence of coherent detection as a multiple access scheme. The proposed multicarrier-CDMA system is simulated using Walsh-Hadamard codes and its performance is compared to that of coherent WDM-OFDM system in terms of bit-error-rate and bandwidth efficiency. It is shown that MC-CDMA benefits from better spectral efficiency while its performance slightly deteriorates in comparison to WDM-OFDM when the number of users is increased.

In the industry, the Modulated IR laser plays an important
role for a lot of gigantic sensor modules and laser
communications between the transmitter and receiver. So far
the method discussed in this paper is about the modulated IR
laser retransmitted wave by the sensor, after sensing the type
modulation of the laser and then transmitting the same laser
again.

This survey paper includes a modernized update on multiple initiatives taken to enhance the perceptual bass. The auditory feeling of the low-frequency pitch is discussed and a vivid analysis of the missing fundamental effect is provided. This paper shows the trend of attempting the virtual bass enhancement in active noise cancelling (ANC) headphones. A wide range of commercial products of the ANC headphones are compared. Moreover, this paper briefly introduces a virtual bass toolbox that is easy to use for beginners and elaborates three main kinds of virtual bass enhancement algorithms. We present some open questions in the last portion of this paper, providing some potential directions for the future research.

In free-space optical communication, the propagation of a laser beam through the atmosphere causes wavefront distortions that decrease the coupling efficiency (CE) from free space to single-mode fiber. This tremendously degrades the performance of the communication channel even in the case of weak turbulence regime. In this Letter, we demonstrate that a multi-actuator adaptive lens working in closed loop with a wavefront sensor can strongly reduce the effect of turbulence while reducing the system complexity with respect to correction systems using deformable mirrors or liquid crystal spatial light modulators. We obtain a three-fold increase in the CE in weak turbulence regime.

—A new scheme for generatinga flat optical frequency comb using three Laser sourcesbased on cascading of Dual Drive Mach Zehnder Modulator (DD-MZM) and Electro Absorption Modulator (EAM) through an optical nonlinear fiber loop is explored in this paper. A single RF signal of 25 GHz having different amplitudes feed into the two arms of DD-MZM and then feed the signal into EAM to modulate the pulse train. By controlling the DC bias of both modulators as well as the RF signal frequency, the scheme is successful in generating evenly spaced 15 flat comb lines among 25 lines with a spectral power variation of about 2dB.The paper compares the performance of the proposed scheme against other methods where only one modulator was used. The scheme is also analysed for producing an optimum number of spectral lines based on number of sources, channel spacing and RF signal frequency. Finally, the performance of the system was successfully evaluated in a preliminary WDM setup of five channels/modes at 10Gb/s for a channel of 1 km length. Results in the form of BER and Q factor are presented in this paper.

In this paper, The author will describe the literature study of optical fiber based-Telecommunication Backbone which aims to describe what is a telecommunication backbone and the benefits of telecommunication backbone. The backbone, or telecommunications backbone, is the nerve center of a very high speed network. The backbone uses the most efficient high-bandwidth technologies. Since the 1990s, optical fiber has become the foundation and standard for this segment of digital networks. However, smaller capacity axes can still be operated in FH (point-to-point Radio Relay) or by Satellite for isolated or island areas. No need to doubt the backbone network because it can reach up to 10 Gbps. With such a high speed, the backbone network is also able to reach networks up to 100 km. In addition, the backbone in the network uses a dual ring technique that is able to provide a fairly high fault tolerance. For those of you who like to download images and stream videos, this backbone network really supports the data transfer traffic.

Представлена отечественная и зарубежная историография, относящаяся к карте Московии, сопоставлены ее описания, сделанные российскими исследователями, а также проведено сравнение экземпляров ксилографий из фондов Российского государственного архива древних актов и библиотеки Св. Марка в Венеции.

The paper discusses the historiography related to Paolo Giovio's 1525 map of Moscovia, critically reviews the descriptions made by the Soviet and Russian researchers to date, and presents a comparative study of the two woodcut copies preserved in the Russian State Archive of Ancient Acts in Moscow (RGADA) and Biblioteca Marciana in Venice.

The concrete elements such as beams, columns, slabs etc., prone to sudden fire break out of fire are subjected to extreme temperatures. Their performance and assessment after exposed to fire becomes necessary to decide upon its fitness and required measures for the repair of different elements. Therefore, it is necessary to understand the changes in the concrete properties due to its exposure to extreme temperatures. It is very essential to know the effect of elevated temperature on the properties of concrete. This paper investigates the effect of sustained elevated temperature on the properties of ordinary concretes of three different grades i.e., M30, M35 and M40 grades, containing 53 grade of cement. The specimens were heated to 150 0 C, 250 0 C and 300 0 C at 1 hour, 2hours and 3hours duration in muffle furnace. They were tested for compressive and split tensile strengths after air cooling to the room temperature. The variables considered in the study include type of cementing material, and temperature. The compressive and tensile strengths of concrete decreased with increasing temperature. And also recron 3s fiber material is used for increasing the strength of the concrete at various temperatures. In this experimental study Recron 3s fiber has been added to concrete in order to enhance the strength characteristics of the concrete in percentages of 0.10%, 0.15%, 0.20%, 0.25%, 0.30%, 0.35% and 0.40% to the weight of concrete and the optimum fiber content for Compressive and Tensile strengths were obtained and it can be used for further study for determining the Compressive and Tensile strengths of the conventional concrete without using recron 3s fiber and concrete with recron 3s fiber material at various elevated temperatures and were observed at 1hour, 2hours and 3hours duration for the age of 7 days to 56 days.

In this paper 10 Gbps WDM systems at 16, 32 and 64 channels have been investigated with EDFA, RAMAN and SOA amplifiers individually and the performance has been compared on the basis of transmission distance and dispersion with and without nonlinearities. It is demonstrated that when the dispersion is 2 ps/nm/km and the number of channels are less, then SOA provide better results because as we increases the number of channels, the gain saturation problem arises due to cross gain modulation, the cross phase modulation and four wave mixing. When dispersion is increased from 2 to 10 ps/nm/km, EDFA provides better results than SOA in the term of BER and output power, but it shows non-uniform gain spectrum. We also observed that RAMAN amplifier provides better results for L band amplification and gain flatting issue because it can substantially reduce the impact of fiber nonlinearity.

In this paper, mode generation based on an elliptical core few mode fiber (EC-FMF) is devised through an inverse function, designed using split step beam propagation method (BPM). The undesired modes from an
EC-FMF are eliminated through an appended waveguide computed from the inverse phase of undesired modes. The EC-FMF may be used as an all-optical switch.

The optical fiber network behaves as the backbone of 5 th generation communication but there are several limitations like attenuation, dispersion, fragility of fiber, splicing and connecting loss and nonlinearities. So, in order to make successful communication it is important to think how signal is transmitted; what amount of signal is transmitted and how long it is transmitted through the fiber. Finally, it is to be investigated the strength of the signal under the effect of Extinction Ratio for the given Fiber length with XPM treatment by OptiSystem 0.17.

Fiber-to-the-home (FTTH) is the broadband network access architecture that uses the existing telecommunication infrastructures to provide the Internet service. The architectures in general are the dedicated active optical network (AON) and distributed passive optical network (PON). The fairness in cost of using the service, fastness in data transmission and the extensibility of fiber access network are the main reasons the FTTH are becoming more popular day by day. The Implementation of a mini FTTH for TU (Loikaw) Campus Network was done through the partial researches: Study on FTTH, Study on Fiber Transmissions, TCP/IP Configurations and Network Design using Switches and Routers. The main aim of this research paper is to be effectively carried out high performance of fiber transmission for a FTTH by both theoretical and practical approaches. To design FTTH network in this university, fiber mainly serves as a transmission medium. Wide bandwidth signal transmission with low delay is a key requirement in present FTTH. Optical fibers provide enormous and unsurpassed transmission bandwidth with negligible latency, and are now the transmission medium of choice for long distance and high data rate transmission in telecommunication networks. To be a perfect fiber link infrastructure, splicing, good performance connector must be considered and take care of component handling. The implementation of fibre link is emphasized on active optical network (AON). For transmission link in AON, the signal degradation is not an issue for this university campus FTTH.

In this article a wearable belt that simultaneously measures the rates of the heartbeat and respiration using an into textile embedded single fiber Bragg grating (FBG) sensor is presented and realized. A miniature interrogator FBGT-600 from Redondo-USA has been used for the measurements. The measured signal has been processed and both the heartbeat and the respiration signals have been separated and visualized.The achieved data proved to be in-line with the common known values measured by other commercial available vital signs measurement systems.

In this paper, we study and analysis Fiber To The Home network. This system will replace the ADSL technology in providing Internet to home users. We discuss the line coding techniques in optical digital communication system.We simulate the FTTH and compare between line codes to choose the suitable line code for the Jordanian FTTH.

Penerapan sistem komunikasi digital untuk monitoring dan pengendalian jarak jauh akan terus berkembang dan semakin banyak diterapkan, karena sistem ini sangat memudahkan operator dalam memantau dan mengontrol plant pada kondisi jarak yang jauh atau pada keadaan cuaca atau lingkungan yang kurang aman. Fiber optik adalah salah satu media transmisi yang dapat menyalurkan informasi dengan kapasitas besar dengan kehandalan keamanan yang tinggi. Makalah ini akan membahas tentang pemantaun dan pengontrolan level tangki jarak jauh dengan sistem SCADA. Hasil utama dari sistem yang diusulkan ini meliputi pengukuran optical power yang diterima pada detektor, menghitung signal to noise ratio pada penerima optik, dan mencari nilai BER. Pekerjaan ini meliputi penggunaan serat optik dengan sepuluh sambungan, yang masing-masing memiliki panjang 2 km.

New age uninvolved optical organization targets giving in excess of 100 Gb/s capacity. Because of late advancement empowering an assortment of optical handsets up to 40 Gb/s, numerous development prospects to 200 G PONs (passive optical network) could be researched. This work proposes two straightforwardly deployable instances of development to 200 G PON dependent on the mix of these improved optical handsets and WDM (wavelength division multiplexing). The actual layer of the optical communication has been reenacted with OptiSystem software to show the correspondence joins exhibitions conduct when considering key segments boundaries to accomplish a great communication plan for a given territory. The unpredictability of the proposed structures and monetary cost examinations are moreover examined. Furthermore, it has been studying the effects of changing bandwidth on the selected channels with respect to the Min Bit Error Rate (BER) parameter.