Optical Fiber Communications

Background: Greenhouses are pivotal to sustainable agriculture as they provide suitable conditions to support the growth of crops in unusable land such as arid areas. However, conventional greenhouse cover materials such as glass, polycarbonate (PC), and polyethylene (PE) sheets are limited in regulating internal conditions in the greenhouses based on environmental changes. Quantum and nonlinear metamaterials are emerging materials with the potential to optimize the covers and ensure appropriate regulation. Objective: This comprehensive review investigated the performance optimization of greenhouse covers through the potential application of nonlinear and quantum metamaterials as nanoadditives, examining their effects on electromagnetic radiation management, crop growth enhancement, and temperature regulation within greenhouse systems. Method: The scoping review method was used, where 39 published articles were examined. Results: The review revealed that integrating nano-additives ensured that the greenhouse covers would block harmful near-infrared (NIR) radiation that generated heat while also optimizing for photosynthetically active radiation (PAR) to promote crop yields. Conclusions: The insights also indicated that the high sensitivity of the metamaterials would facilitate the regulation of the internal conditions within the greenhouses. However, challenges such as complex production processes that were not commercially scalable and the recyclability of the metamaterials were identified. Future work should further investigate pathways to produce hybrid greenhouse covers that integrate metamaterials with conventional materials to enhance scalability.

Over the past several years, high-speed vertical-cavity surface-emitting lasers (VCSELs) have been the subject of intensive worldwide research due to their applications in optical interconnects and optical data networks. The performance of VCSELs, especially with respect to their high-speed characteristics, has made significant progress. In this chapter, we first present the basic theory for current-modulated VCSELs using rate equations and small-signal analysis. Factors that affect the modulation bandwidth, including the intrinsic laser responses and extrinsic parasitics, are identified. Once these limitations are known, we discuss various designs that have been implemented in VCSELs to specifically address them, followed by a review of the current high-speed VCSEL performance based on these designs at several different wavelengths, including 850 nm, 980 nm, 1.1 μm, and 1.3–1.6 μm. Finally, we consider new modulation schemes based on loss modulation in coupled-cavity VCSELs, which ...

Photonic integrated circuits (PICs) enable construction of complex optical systems at a miniaturized scale not possible with bulk elements. All active and passive components required to fabricate chip-scale coherent lidar systems have been demonstrated and system demonstrations are currently underway. In this paper we describe our efforts to demonstrate a chip-scale frequency modulated continuouswave (FMCW) lidar. This system incorporates wavelength tuning and phased array operation to enable 2D non-mechanical beam steering. We further discuss approaches aimed at scaling aperture dimensions from mm scales to 1 cm and 10 cm scales. These efforts include development of micron-sized mirror arrays to enable coupling between optical layers and demonstration of wafer-scale routing of light at high efficiency.

We carried out modeling and simulation of the noise properties associated with types of modal oscillations induced by scaling the asymmetric gain suppression (AGS) in multimode semiconductor lasers. The study is based on numerical integration of a system of rate equations of 21-oscillating modes taking into account the self-and cross-modal gain suppression mechanisms. AGS is varied in terms of a predefined parameter, which is controlled by the linewidth enhancement factor and differential gain. Basing on intensive simulation of the mode dynamics, we present a mapping (AGS versus current) diagram of the possible types of modal oscillations. When the laser oscillation is hopping multimode oscillation (HMMO), the spectra of relative intensity noise (RIN) of the total output, and hopping modes are characterized by a sharp peak around the relaxation oscillation frequency and a broad peak around the hopping frequency. The levels of RIN in the regimes of single-mode oscillation are much lower than those under HMMO, and the mode-partition noise is two orders of magnitudes lower.

5G networks have arrived and are able to shift paradigms within the areas of connectivity, maintainability, scalability and availability. Their aim is to ensure that users can remain online with their devices at any time and in any place. In light of this, solutions for centralized networks are becoming attractive since they are manageable and low-cost. In these conditions, the use of computing techniques such as fuzzy logic benefits the supervision and planning of networks by optimizing and controlling resources as well as managing the system. However, planning a centralized network tends to raise challenges in the optical sectors that are located between the telecommunications center and the base station. Technologies such as radio over fiber are being examined to meet the demands in the fronthaul market, although they raise many other challenges. For this reason, in this study, we have adopted an intelligent strategy to determine in a balanced way which radio over fiber signals should be allocated in the optical sector. This strategy is implemented using fuzzy logic and may be used in decision making to plan the future of centralized networks. The results show that it is possible to make tradeoffs between the capital expenditure and performance of the system.

Free Space Optical Communications (FSO) has become a magnet for a variety of applications in the communication field. Signal attenuation was highlighted in data transfer, particularly in the multimedia e.g. high-speed video camera network requires sufficient throughput. This paper focuses on finding an approach to improve the signal received through the use of bi-directional FSO multiple access channel with high transmission power to avoid signal attenuation in short distances over atmospheric turbulence channels. Comparison of the extracted results proved that the performance of the proposed system is effective to overcome these effects.

Tableau 1.1 : Symboles normalisés pour la représentation des appareils de connexion….….3 Tableau 1.2 : Contrôle des composants ou des fonctions d'un disjoncteur………………..…19 Tableau 2.1 : Courants de court-circuit selon CEI 60909 …………………………………....27 Tableau 3.1 : Comparaison entre le modèle de Mayr et le modèle de Cassie………………...43 Chapitre 03 Les modèles d'arc à boite noire Chapitre 03 Les modèles d'arc à boite noire

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The purpose of the project is to provide security for woman. In case of emergency situations woman will press an emergency button which will activates the GPS for location tracking and a SMS is sent to the police and family members of woman along with time. The main idea of our project is to help the women's to prevent the increase in regular kidnap and chain snatchings. Here we are providing three methods of Safety and security for women. In each method there will be an alertness that is sent to the existing Phone Numbers through GSM technology. The purpose of using GPRS is that to track the location and position. Also a Smart Phone app is developed for controlling and alert system.

The problem of routing and wavelength assignment (RWA) is critically important for increasing the efficiency of wavelength-routed all optical networking. So performance analysis of RWA algorithm is required for different topologies so that we use topologies for specific application example: (two way video communications). To increase the link utilizations and to reduce call blockage, the topology comparison is important. Topologies used in this paper for checking the performance of RWA are random, ring, star, and tree. In this paper we used First-fit algorithm for assigning wavelength and Dijkstra'srouting algorithm for shortest path for different topologies. It is shown that, under dynamic arising of calls the star topology performs the best on blocking probability, and also call blocking ratio (CBR) is 7% and CPU time 0.5sec.Comparative analysis has been done for different topologies. Performance analysis has been done by considering various topologies for a dedicated network.

Current optical fiber communication is increasingly limited by bottlenecks such
as channel utilization or hardware limitations, highlighting the need for more
efficient systems. Manipulating the information system by encoding the infor-
mation in higher-order bases (binary to hexadecimal) and using permutations
and several properties of tunable lasers, such as phase and wavelength, can pro-
duce higher data transmission speeds. We propose a solution through phase
and chromatic modulation by tuning laser frequencies and laser drive currents
along with permutation encoding. Signals are decoded by spectroscopes, which
detect phase and color after being corrected. Most importantly, this system
operates under the limit established by Shannon’s theorem for noisy channels.
This multi-dimensional approach provides a terabit-scale throughput depending
on the number of lasers in the array (6 Tb/s to 230 Tb/s, or 27 to 32 bits per
symbol per laser). This system gives higher data rates than current telecom
technology. It also offers a higher information density with reduced energy and
cost.

En este trabajo empleamos la proyeccion de luz estructurada para la digitalizacion tridimensional de la topografia de superficies de objetos milimetricos. Esto se logra cuando un patron de luz formado por lineas claras y oscuras es modulado al ser proyectado sobre la superficie de un objeto mientras es observado a traves de un microscopio optico. La imagen que se obtiene es capturada con una camara CCD y almacenada en una computadora. Mediante el procesamiento digital de las imagenes obtenidas es posible visualizar la topografia de las superficies.

Butt-joint integrated extended cavity InAs/InP (100) quantum dot (QD) Fabry-Pérot laser devices emitting around 1.55 µm are demonstrated. Continuous wave lasing at room temperature is realized with devices of different lengths. The threshold currents, transparency current density, and external differential quantum efficiency are all comparable to those of all-active QD lasers. The Butt-joint reflectivity for straight waveguides is below -40 dB. Light versus current curves and lasing spectra reveal that for low current, lasing starts on the QD ground state transition, while excited state lasing sets in with increasing current.

With the recent data rate increase it is very challenging to build a fibre optic network that would enable a high data rate transmission over a long haul distance. The signal suffers large degradation over a certain distance due to distortion by the nonlinear effects of the optical fibres. In particular, transmission of high data rates over existing fibre optic systems, while keeping the cost low, avoiding an increase of the system's complexity and the usage of expensive devices, would be a very challenging task. In this paper, we address this problem by increasing the transmission distance in the fibre optic links for up to 2500km. We have used Standard Single Mode Fibre (SSMF) and Dispersion Compensation Fibre (DCF), where DCF is used as a loss compensator in Radio-Over-Fibre (RoF) systems. A mixture combination of the pre, post and symmetrical fibre compensation schemes were developed to overcome the dispersion in the fibre. We have found that in order to achieve high RF over fibre optic system performance for high data rates and long transmission, there is a requirement to upgrade the optical configuration scheme in a proportional way, by raising the length of the fibre span, compensation span and amplification. We have reported optimised RF over fibre configuration schemes that would have a great impact on reducing the cost, reducing the system's complexity and avoiding usage of expensive devices, in order to achieve high data rate transmission over existing fibre optic systems.

Verlange nicht, dass alles, was geschieht, so geschieht, wie du es willst, sondern wünsche dir, dass alles so geschieht, wie es geschieht, und du wirst glücklich sein. Epiktet (geb. um 50 n. Chr., ges. um 140 n. Chr.), "Handbuch der Moral" v Preface HE WORK FOR THE PRESENT DISSERTATION has been carried out at the IHP (Institute for High Performance microelectronics) in Frankfurt an der Oder, Germany, as part of the so-called Wireless Broadband Networks (WBN) Project under supervision of Professor Rolf Kraemer and is to be submitted to the Faculty of Informatics at the Brandenburgische Technische Universität (BTU) Cottbus. I would like to thank Professor Kraemer for the confidence he put on me when starting this Project in 1999, providing me the possibility to carry out a Ph.D. without being directly involved at the University. The author would also like to thank all the members of the WBN Project for their support and in particular Dr. Eckhard Grass for his great work as project leader, Dr. Gunther Lippert and Mr. Ulrich Jagdhold for their support in the difficult initial moments. I want to express my sincere gratitude to Dr. Koushik Maharatna and Mr. Miloš Krstić for their contributions in this Dissertation. Several of the proposals given in this work have materialized thanks to their experience in digital design. Also, thank you very much indeed for your contributions, discussions and corrections to all our co-authored papers. Beyond the call of duty, Koushik has been a great friend with whom the tough days commuting from Berlin to Frankfurt became more pleasant. I would like to give my warmest thanks to my parents, Ildefonso Troya Márquez and María Dolores Chinchilla López for their moral support while staying far away from home. This work is dedicated to all the friends from several nationalities I have met in Frankfurt (Oder), and specially to Nina. Our Souls joined each other in Frankfurt, and so they will remain forever.

In this research, a temperature measurement technique was developed using fiber optic structured SMS and OTDR. Where in optical fibers singlemode-multimode-singlemode (SMS) and Optical Time Domain Reflectometer (OTDR) has been widely used for various sensors in detecting damage to the building earlier. Thereafter, calculations are performed using Borland Delphi's Lagrange Interpolation method 7. Characteristics of each of the fiber-optic fiber sensor structures that have been fabricated using multimode optical fibers with lengths of 5.5 cm, 6 cm, 6.5 cm and 7 cm and with use its operating wavelength is 1310 nm. Testing rangesuhusebesar 37oC - 67oC with every temperature rise of 10oC.Berdasarkan research results, multimode length 5.5 cm there is a graph increase with R2 of 93.7%. The increase in temperature, the loss of power generated greater. While the multimode length 6 cm, 6.5 cm, and 7 cm indicate that there is a decrease graph, for multimode length 6 cm with R2 equal to 97,...

Non linearity effects arose as optical fiber data rates, transmission lengths, number of wavelengths and optical power levels increased. The only worries that plagued optical fiber in the early day were fiber attenuation and sometimes, fiber dispersion; however, these issues are easily dealt with using a variety of dispersion avoidance cancellation techniques. Fiber nonlinearities present a new realm of obstacles that must be overcome. The nonlinearities previously appeared in specialized applications such as undersea installations. However the new nonlinearities that need special attention when designing fiber optic system include stimulated brillouin scattering (SBS), stimulated Raman Scattering (SRS), four wave mixing (FWM), self phase modulation (SPM), cross phase modulation (XPM) and intermodulation. Fiber nonlinearities represent the fundamental limiting mechanism to the amount of data that can be transmitted on a single optic fiber. This thesis presents a study of these limitations and the steps that can be taken to minimize the effect of nonlinearities. The effect of nonlinearities at different data rates and effective length of fiber have been studied. The data rates, transmission lengths and the channel spacing have to be optimized in order to have an efficient transmission without any nonlinear effect. The non-linear effects tends to manifest themselves when optical power is very high, they become important in DWDM. FWM is one of the dominating degradation effects in WDM systems with dense channel spacing. If the channels are equally spaced, the new waves generated by FWM will fall at channel frequencies and will give rise to crosstalk. The effect of FWM at various channel spacing in WDM systems have been studied in this thesis, however the optimum channel spacing, effective length and cross-sectional area have to be found. Effect of nonlinearities and hence the choice of data format (NRZ, RZ, NRZ raised cosine, RZ raised cosine) have to be worked upon. Apart from FWM, SPM and XPM also degrade the system performance. All these nonlinearities along with chromatic dispersion have been studied. It is found that some amount of chromatic dispersion can minimize the nonlinearities. The simultaneous if compensation of dispersion and nonlinearities is presented.

In a fiber-optic system at long distances or high data rates, the system can be limited either by the losses (attenuation-limited transmission) or, assuming that the link is not limited by the source or detector speed, by the dispersion of the fiber (dispersion-limited transmission).In this paper we demonstrate how the optimum link length can be determined in different aspects like Dispersion & attenuation.

In this paper; dispersion compensating fibers are used to compensate for the positive dispersion accumulated over the length of fiber. Post dispersion compensation scheme is employed for dispersion compensation. SINE modulation format is employed. The performance of this scheme is analyzed and then the optimization of this scheme is done by different wavelengths of C band. The investigation is done on detailed simulative analysis using optisystem.

A compact and tunable Erbium-doped fiber laser is demonstrated using a highly concentrated Erbium-doped fiber in conjunction with a microfiber Mach-Zehnder interferometer (MMZI) structure for the first time. A stable laser output is achieved at 1531.7 nm region with a peak power of -19 dBm and an optical signal to noise ratio of 30.1 dB using a 980-nm pump at 100 mW power. The operating wavelength of the laser can be tuned from 1530.2 to 1532.7 nm by changing the path length difference (PLD) inside the MMZI from 1.6 to 2.7 mm at room temperature. It is also observed that the operating wavelength linearly shifts to a longer wavelength as the PLD increases with a tuning slope efficiency of 0.17 nm/mm. The tuning ability is due to the alteration of the induced optical phase shift inside the MMZI which affects the optical interference and the dominant peak which is responsible for the lasing action.

The performance of an asynchronous phase-encoded optical code-division multiple-access system is evaluated in a dispersive fiber medium. We derive an approximate analytical expression for the root mean square width of the phase-encoded signal (pseudorandom optical signal with low intensity) propagating in linear dispersive fibers. Bit-error rate analysis of the system is performed in the case of both ordinary single-mode fiber and dispersion-shifted fiber (DSF). The numerical results demonstrate that even though system performance improves due to the smaller width of initial Gaussian optical pulse, the effect from dispersion is higher. Larger code length reduces the effect of dispersion and the use of DSF greatly increases the transmission distance.

GHz wireless local area networks (WLANs) standards (e.g., IEEE 802.11ad and IEEE 802.15.3c) employ hybrid MAC protocols consisting of contention based access using CSMA/CA as well as dedicated service periods using time division multiple access (TDMA). To provide the channel access in the contention part of the protocol, quasi omni (QO) antenna patterns are defined which span over the particular spatial directions and cover a limited area around access points. In this paper, we propose an algorithm to determine the beamwidth of each QO level. The proposed algorithm takes into account the spatial distribution of nodes to allocate the beamwidth of each QO level in an adaptive fashion in order to maximizes the channel utilization and satisfy the required link budget criterion. Since the proposed algorithm minimizes the collisions, it also minimizes the average time required to transmit total packets in a QO level. Proposed algorithm improves the average channel utilization up to 20-30% and reduces the time required to transmit total packets up to 40-50% for the given network parameters.

GHz wireless local area networks (WLANs) standards (e.g., IEEE 802.11ad and IEEE 802.15.3c) employ hybrid MAC protocols consisting of contention based access using CSMA/CA as well as dedicated service periods using time division multiple access (TDMA). To provide the channel access in the contention part of the protocol, quasi omni (QO) antenna patterns are defined which span over the particular spatial directions and cover a limited area around access points. In this paper, we propose an algorithm to determine the beamwidth of each QO level. The proposed algorithm takes into account the spatial distribution of nodes to allocate the beamwidth of each QO level in an adaptive fashion in order to maximizes the channel utilization and satisfy the required link budget criterion. Since the proposed algorithm minimizes the collisions, it also minimizes the average time required to transmit total packets in a QO level. Proposed algorithm improves the average channel utilization up to 20-30% and reduces the time required to transmit total packets up to 40-50% for the given network parameters.

The exploitation of the spatial dimension in space division multiplexing (SDM) is a promising solution for increasing the transmission capacity and substantially improving the spectrum efficiency. Orbital angular momentum (OAM) is one of the most attractive approaches of SDM that observes increasing interest either in free space or in optical fiber communications. In this work, we design optimized graded index-few mode fibers (GI-FMFs) supporting 20 eigenmodes with high intermodal separation (≥1 × 10 -4 ) between vector modes; hence limiting intermodal coupling and favoring the formation of 12 OAM modes. To the best of our knowledge, this is the highest OAM number reported in the well-known graded index fiber. We investigate numerically the effects of the shape parameter (α) on the supported vector modes and on the properties of OAM channels in the GI-FMFs. We evaluate their associated differential group delay (DGD) and purity. The selected designs are proposed as viable candidates for short haul connections.

In this paper, we experimentally demonstrate a radar signal distribution over optical networks. The use of fiber enables us to distribute radar signals to distant sites with a low power loss. Moreover, fiber networks can reduce the radar system cost, by sharing precise and expensive radar signal generation and processing equipment. In order to overcome the bandwidth challenges in electrical switches, a semiconductor optical amplifier (SOA) is used as an all-optical device for wavelength conversion to the desired port (or channel) of a wavelength division multiplexing (WDM) network. Moreover, the effect of chromatic dispersion in double sideband (DSB) signals is combated by generating optical single sideband (OSSB) signals. The optimal values of the SOA device parameters required to generate an OSSB with a high sideband suppression ratio (SSR) are determined. We considered various parameters such as injection current, pump power, and probe power. In addition, the effect of signal wavelength conversion and transmission over fiber are studied in terms of signal dynamic range.

Dispersion management in few mode fiber (FMF) technology is crucial to support the upcoming standard that reaches 400 Gbps and Terabit/s per wavelength. Recently in Chebaane et al. ( ), we defined two potential differential mode delay (DMD) management strategies, namely sawtooth and triangular. Moreover we proposed a novel parametric refractive index profile for FMF, referred as raised cosine (RC) profile. In this article, we improve and optimize the RC profile design by including additional shaping parameters, in order to obtain much more attractive dispersion characteristics. Our improved design enabled to obtain a zero DMD (z-DMD), strong positive DMD (p-DMD) and near-zero DMD (nz-DMD) for six-mode fiber, all appropriate for dispersion management in FMF system. In addition, we propose a positive DMD (p-DMD) fiber designs for both, four-mode fiber (4-FMF) and six-mode fiber (6-FMF), respectively, having particularly attractive dispersion characteristics.

Spatial mode-division multiplexing (MDM) that exploits the emerging fewmode fiber (FMF) technology is one potential candidate for next-generation petabyte optical communication links. In this paper, we focus on the design issues and specifications of the next-generation FMF that will better enable future MDM networks. These systems suffer from two main optical fiber impairments: intermodal coupling and dispersion. In this paper, we focus on the dispersion management issues through an FMF optical link. We first define two potential differential mode group delay (DMD) management strategies, namely, sawtooth and triangular. Moreover, we propose and investigate a novel parametric refractive index profile few-mode fiber, referred to as raised cosine (RC) function, which has been extensively used in digital communication pulse shaping. We investigate the achievable DMD for a wide range of the RC shape parameter and identify the design values of a two-mode FMF fiber. We then improve the RC profile by including additional shaping parameters. This enabled us to develop one four-mode fiber (4-FMF) and one six-mode fiber (6-FMF) having particularly attractive dispersion characteristics for three kinds of FMF applications: nz-, p-, and n-DMD.

High frequency characterisation of three-quantum well GaInNAs= GaAs lasers operating at 1.35 mm is reported. A relaxation frequency as high as 7.4 GHz and a 9.7 GHz small-signal bandwidth are demonstrated, indicating the potential for high bit rate (10 Gbit=s) direct modulation of these dilute nitrides on GaAs devices.

We investigate InAs/GaAs quantum dot (QD) lasers grown by gas source molecular beam epitaxy with different growth temperatures for InAs dot layers. The same laser structures are grown, but the growth temperatures of InAs dot layers are set as 425 and 500 • C, respectively. Ridge waveguide laser diodes are fabricated, and the characteristics of the QD lasers are systematically studied. The laser diodes with QDs grown at 425 • C show better performance, such as threshold current density, output power, internal quantum efficiency, and characteristic temperature, than those with QDs grown at 500 • C. This finding is ascribed to the higher QD density and more uniform size distribution of QDs achieved at 425 • C.

A compact and tunable Erbium-doped fiber laser is demonstrated using a highly concentrated Erbium-doped fiber in conjunction with a microfiber Mach-Zehnder interferometer (MMZI) structure for the first time. A stable laser output is achieved at 1531.7 nm region with a peak power of -19 dBm and an optical signal to noise ratio of 30.1 dB using a 980-nm pump at 100 mW power. The operating wavelength of the laser can be tuned from 1530.2 to 1532.7 nm by changing the path length difference (PLD) inside the MMZI from 1.6 to 2.7 mm at room temperature. It is also observed that the operating wavelength linearly shifts to a longer wavelength as the PLD increases with a tuning slope efficiency of 0.17 nm/mm. The tuning ability is due to the alteration of the induced optical phase shift inside the MMZI which affects the optical interference and the dominant peak which is responsible for the lasing action.

Transmission in the 60 GHz frequency band performs poorly in long-distance direct links due to the large path loss. The received signal strength can be relatively weak if the line-of-sight path is blocked by obstacles. A device cooperation approach, which effectively combats the severe path loss thereby improving the overall throughput for wireless personal area networks (WPANs), is proposed in this paper. Throughput maximization is formulated as a linear programming problem and the optimal solutions are provided in each case. Comprehensive simulations are performed to quantify the performance of the cooperative approach with different antenna models and spatial reuse strategies. The effect of minor-lobe, imperfect information and other factors are investigated under different network settings. The performance analysis presented here can provide guidelines for the design of cooperative 60 GHz WPANs.

Characterizing the fundamental response and operational parameters of a deformable mirror is a critical first step in the design of an adaptive optics system. This paper describes the characterization and training of a piezoelectric deformable mirror (PDM) to be implemented on a low order Adaptive Optics (AO) system at Short Wave Infrared (SWIR) wavelengths for free-space optical communications systems. The data were analyzed using commercial and customized software.

We demonstrate a curvature sensor with a newly designed photonic crystal fiber of high birefringence (Hi-Bi PCF). The proposed PCF has two large air holes in the outer cladding region that give rise to core ellipticity during the fabrication process. The curvature sensor is based on the PCF Sagnac interferometer, the output spectrum shift of which provides information on the PCF curvature. It turns out that the curvature sensitivity depends on the bending directions with respect to the large-air-hole alignment. For the two orthogonal bending directions, the curvature sensitivities near 1480 nm are À1:87 nm/m À1 (parallel to the axis of the two large air holes) and 1.24 nm/m À1 (perpendicular to the axis of the two large air holes), respectively, and are also insensitive to environmental temperature variation. The proposed curvature sensor may be useful in thin structural deflection measurement.

We describe polarization-sensitive phase-referenced linear optical sampling for measuring polarization, amplitude, and phase of a high speed optical waveform. With a single measurement, we simultaneously measure both orthogonal polarization channels of 2×10 GB/s polarization-multiplexed QPSK.

The number of plug-in electric vehicles (PEV) increased significantly over the past few years and is expected to increase further in the next years due to environmental concerns and fossil fuel depletion. Distribution systems were not originally designed to accommodate this continuous prevalence of PEVs, challenging system planners to install parking lots (PLs) that support PEV charging. The literature has presented many studies for planning PLs, although it did not consider the vehicle-to-grid (V2G) contribution to improving system reliability. This paper proposes an optimal planning framework for allocating and sizing the PLs of PEVs incorporating V2G to improve the reliability of distribution systems. A combined probabilistic model of Markov Chain Monte Carlo simulation (MCMCS) and Monte Carlo simulation (MCS) is applied to capture the stochastic existence of PEVs in PLs. Reliability is evaluated based on a group of energy-oriented indices and the customer's annual cost of interruption. A comprehensive investigation is presented to test the proposed framework on a distribution system for grid-to-vehicle (G2V) and V2G case studies. The results show the efficiency of the proposed framework in improving the reliability indices by

Orthogonal frequency division Multiplexing (OFDM) is a new multicarrier modulation scheme and strongly efficient in bandwidth usage. It have less ICI (Inter carrier interference), ISI(Inter symbol interference) and good spectral and power efficiency. OFDM provide a high speed wireless communication and most high speed wireless communication system uses OFDM for transmission e.g. IEEE 802.11, IEEE 802.16, IEEE 802.20..An OFDM baseband signal is the sum of a number of orthogonal sub-carriers. The sub-carriers being independently modulated by using QAM or PSK or by its own data. The orthogonality between subcarrier allows a lot of sub-carriers can be transmitted simultaneously in a tight frequency space without interference from each other by saving the bandwidth and they are able to overlap without interfering. So OFDM systems provide good spectral efficiency without causing adjacent channel interference (ACI). Since many subcarrier components are added via an inverse fast Fourier tra...

Using stable power in the infrastructure network of Hybrid Fiber Coaxial (HFC) NODEs is a major concern and a priority. A NODE is an active device that requires a supply of electrical energy to operate. The same applies to outdoor cabinets. This is where the active equipment of the Fiber-to-the-Home (FTTH) network is located. An outdoor cabinet as the location of active devices in the Fiber To The Home network becomes a system for efficient power consumption of the Fiber To The Home network in a hybrid fiber coaxial network. Electrical loads such as DC power systems, air conditioning (Aircond), optical line termination (OLT), and switches are the major electrical loads that require power in outdoor Fiber To The Home (FTTH) closets. Research suggests that FTTH networks are more energy efficient than HFC networks, using up to 70% less energy per user. This ongoing study focuses on demonstrating the impact of the network reconstruction conversion process on the power consumption efficiency of an existing network, Hybrid Fiber Coaxial (HFC), to his FTTH (Fiber To The Home) network. And the savings in monthly electricity bills with continued use of HFC technology are about 16% of the monthly bill.

We fabricate a GaAs-based InGaAs/InGaAsP multiple quantum wells (MQWs) laser at 1.55 μm. Using two-step growth method and thermal cyclic annealing, a thin low-temperature InP layer and a thick InP buffer layer are grown on GaAs substrates by low-pressure metal organic chemical vapor deposition technology. Then, highquality MQWs laser structures are grown on the InP buffer layer. Under quasi-continuous wave (QCW) condition, a threshold current of 476 mA and slope efficiency of 0.15 mW/mA are achieved for a broad area device with 50 μm wide strip and 500 μm long cavity at room-temperature. The peak wavelength of emission spectrum is 1549.5 nm at 700 mA. The device is operating for more than 2000 h at room-temperature and 600 mA.

In this paper, UWB direction finding technique using digital channelization receiver architecture is proposed. The basic idea of this technique is to split the UWB array output into multiple frequency channels and then down-convert each channel into much lower frequency, hence allowing the low sampling rate ADC to be used. Estimation of the DoA of UWB source is achieved by forming a direction finding function using the spectral information from channelizer's output. A thorough performance analysis from simulation results is presented to verify the proposed technique and to investigate the effect of the system's parameters on the performance.

In this letter, we propose an alternative approach for UWB direction finding using hybrid digital-analog technique. The proposed system uses an array of leading-edge pulse detection scheme in analog domain. The detection scheme is realized using tunnel diode with envelope detector and comparator latch, whose output is digital binary signal. The outputs of all array branches are then summed up to form a staircaseshaped waveform, whereby the slope of the waveform indicates the direction of impinging UWB signal. In order to detect the slope and produce the estimation of the direction, an analog differentiator joint with a peak detector is utilized. The proposed system is relatively simple and does not require high sampling rate or high speed DAC.

The influence of the electrical phase modulation index h in the performance of constant-envelope orthogonal frequency division multiplexing (CE-OFDM) in coherent detection optical systems is treated analytically and its range of validity examined by simulations. A compromise between h and subcarrier mapping is identified according to differences in sensitivity related to non-linearities inserted by the optical modulator. It is shown that the proposed scheme outperforms conventional coherent detection OFDM systems, which is strongly dependent on both phase and optical modulation indexes.

In this paper we describe realization of components for signal processing for millimeter wave digital radio with DBPSK modulation. System characteristics are tuned to satisfy operation at 58-63GHz band, according to European standards. Actual system is tuned to 200Mbit/s, but entire concept could be easily expanded to 1Gbit/s. All system components are described in detail.

The potential to operate third-party terminals over multi-domain transparent optical networks attracts operators and customers to implement Optical Spectrum as a Service (OSaaS). As infrastructure information cannot always be shared with OSaaS end customers, alternatives to off-line Quality of Transmission (QoT) estimation tools are required to assess the performance of the spectrum slot in order to estimate achievable throughput. In this paper, commercially available sliceable coherent transceivers are used to assess the Generalized Signal To Noise Ratio (GSNR) based QoT of the OSaaS in a live production network for both, narrow-band and wide-band OSaaS configurations. Extended channel probing based on symbol rate variability is combined with spectral sweeping and operation regime detection to characterize OSaaS implementations on 17 links with different underlying infrastructure configurations in order to maximize capacity and increase service margins in a low-margin operation regime. We achieve 0.05 dB estimation accuracy in GSNR for a wide-band spectrum services and 0.32 dB accuracy for narrow-band spectrum services. Based on the GSNR profile, spectral misalignment, spectral ripple and operation regime are detected and service margin improvements are demonstrated. Finally, we discuss the network optimization perspective based on acquired data from channel probing and propose use-cases for continuous channel probing in transparent optical networks.