Performance Optimization of Optical Amplifiers for High Speed Multilink Optical Networks using Different Modulation Techniques

Abstract Next generation optical networks require large capacity communication networks for proper utilization of gain bandwidth of the networks. Optical amplifiers with wavelength division multiplexed (WDM) systems are the key technologies for the realization of these networks. In this paper, we have investigated the performance of the networks using different modulation techniques, such as return-to-zero (RZ), non-return-to-zero (NRZ) and duobinary. Attempts were taken to design 8 channels, 10 Gbps WDM network at channel spacing of 0.8 nm. An innovative model with EDFA-Raman amplifier is designed to examine the performance of the different modulation schemes. From the results, it is found that NRZ configuration gives maximum output power and good quality of communication as compared to other modulation schemes. Further, it is seen that with increase in channel dispersion from 2 to 4 ps/nm/km, the quality of the signal started decreasing.

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Performance Evaluation of Optical Amplifiers for High-Speed Optical Networks

Journal of Optical Communications ◽

10.1515/joc-2017-0133 ◽

2019 ◽

Vol 41 (1) ◽

pp. 15-21 ◽

Cited By ~ 1

Author(s):

Deepak Malik ◽

Geeta Kaushik ◽

Amit Wason

Keyword(s):

Quality Factor ◽

Optical Networks ◽

Communication Systems ◽

High Speed ◽

Optical Amplifiers ◽

Long Distance ◽

Communication Signals ◽

Eye Opening ◽

Eye Closure

Abstract Optical networks were invented by the developing and developed nations in order to extend the capacity required for communication systems in a worthwhile way. In this paper, the attempt is done to improve the capacity and performance of semiconductor optical amplifier, Raman and erbium-doped fiber amplifier (EDFA) amplifiers used in optical networks. The potential of different optical amplifiers operating at 8×10 Gbps has been examined and their performance was compared on behalf of different parameters, viz. eye opening, eye closure, jitter, quality factor and transmission distances. It was observed that EDFA provided the consistent good quality of communication for long-distance transmission up to 150 km along with better eye opening and eye closure with acceptable jitter performance. Further, it is observed on the basis of quality factor and bit error rate that EDFA gives comparably better performance than Raman amplifier. Moreover, it is seen that as the data rate of the system increases, the quality of communication signals starts decreasing.

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Analytical and Simulation Fair Comparison of Three Level Si IGBT Based NPC Topologies and Two Level SiC MOSFET Based Topology for High Speed Drives

Energies ◽

10.3390/en12234571 ◽

2019 ◽

Vol 12 (23) ◽

pp. 4571 ◽

Cited By ~ 2

Author(s):

Jelena Loncarski ◽

Vito Giuseppe Monopoli ◽

Riccardo Leuzzi ◽

Leposava Ristic ◽

Francesco Cupertino

Keyword(s):

Output Power ◽

Heat Sink ◽

High Speed ◽

Dynamic Models ◽

Maximum Output Power ◽

Life Time ◽

Experimental Tests ◽

Oxide Semiconductor ◽

Maximum Output ◽

Fair Comparison

Wide bandgap (WBG) power devices such as silicon carbide (SiC) can viably supply high speed electrical drives, due to their capability to increase efficiency and reduce the size of the power converters. On the other hand, high frequency operation of the SiC devices emphasizes the effect of parasitics, which generates reflected wave transient overvoltage on motor terminals, reducing the life time and the reliability of electric drives. In this paper, a SiC metal-oxide-semiconductor field-effect transistor (MOSFET) based two level (2L) inverter is systematically studied and compared to the performance of Si insulated-gate bipolar transistor (IGBT) based three level (3L) neutral point clamped (NPC) inverter topologies, for high speed AC motor loads, in terms of efficiency, overvoltages, heat sink design, and cost. A fair comparison was introduced for the first time, having the same output voltage capabilities, output current total harmonic distortion (THD), and overvoltages for the three systems. The analysis indicated the convenience of using the SiC MOSFET based 2L inverter for lower output power. In the case of the maximum output power, the heat sink volume was found to be 20% higher for the 2L SiC based inverter when compared to 3L NPC topologies. Simulations were carried out by realistic dynamic models of power switch modules obtained from the manufacturer’s experimental tests and verified both in the LTspice and PLECS simulation packages.

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High-Speed and High-Power 940 nm Flip-Chip VCSEL Array for LiDAR Application

Crystals ◽

10.3390/cryst11101237 ◽

2021 ◽

Vol 11 (10) ◽

pp. 1237

Author(s):

Kuo-Bin Hong ◽

Wei-Ta Huang ◽

Hsin-Chan Chung ◽

Guan-Hao Chang ◽

Dong Yang ◽

...

Keyword(s):

High Power ◽

High Speed ◽

Flip Chip ◽

Maximum Output Power ◽

Thermal Characteristics ◽

Cavity Surface ◽

Maximum Output ◽

Two Samples ◽

Vertical Cavity Surface ◽

Surface Emitting Laser

In this paper, we demonstrate the design and fabrication of a high-power, high-speed flip-chip vertical cavity surface emitting laser (VCSEL) for light detection and ranging (LiDAR) systems. The optoelectronic characteristics and modulation speeds of vertical and flip-chip VCSELs were investigated numerically and experimentally. The thermal transport properties of the two samples were also numerically investigated. The measured maximum output power, slope efficiency (SE) and power conversion efficiency (PCE) of a fabricated flip-chip VCSEL array operated at room-temperature were 6.2 W, 1.11 W/A and 46.1%, respectively. The measured L-I-V curves demonstrated that the flip-chip architecture offers better thermal characteristics than the conventional vertical structure, especially for high-temperature operation. The rise time of the flip-chip VCSEL array was 218.5 ps, and the architecture of the flip-chip VCSEL with tunnel junction was chosen to accommodate the application of long-range LiDAR. The calculated PCE of such a flip-chip VCSEL was further improved from 51% to 57.8%. The device design concept and forecasting laser characteristics are suitable for LiDAR systems.

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Analisis Unjuk kerja Jaringan Microcell LTE Berdasarkan Variasi Level Modulasi

AITI ◽

10.24246/aiti.v16i2.99-114 ◽

2020 ◽

Vol 16 (2) ◽

pp. 99-114

Author(s):

Shafira Fajrin Arumsidi ◽

Anggun Fitrian Isnawati ◽

Ade Wahyudin

Keyword(s):

Communication Networks ◽

High Speed ◽

Streaming Video ◽

Average Throughput ◽

Current Increase ◽

Modulation Techniques ◽

Different Types ◽

User Capacity ◽

E Mail ◽

Modulation Level

The development of telecommunications technology continues to increase, especially in the use of cellular communication networks. Users of cellular networks today need high-speed communication to be able to enjoy the facilities offered such as streaming video, web browsing, e-mail and others. With the current increase in user capacity, it causes a lot of interference. Therefore, the use of modulation techniques needs to be considered. To find out the proper use of modulation, in accordance with the conditions of the region and the network used, this study examines the performance of variations in modulation levels, namely QPSK, 16QAM, 64QAM and 256QAM. The parameters measured in this study include RSRP, CINR, BER, user connected and throughput. Based on the coverage by RSRP simulation results, it was found that the RSRP did not change because the power signal will always adjust to any use of the modulation level. For coverage by CINR obtained to obtain a higher rate value, a higher CINR value is needed and for coverage by BER parameters, BER does not affect the bit per symbol carried by each modulation, only affects the different types of modulation. Meanwhile, in the capacity by Throughput parameter, QPSK modulation produces the lowest average throughput value of 14.01 Mbps followed by 16QAM 21.58 Mbps 64QAM 28.6 Mbps and 256QAM 33.87 Mbps. In addition, for the capacity by user connected parameters all connected users on all modulation used will produce 100% for capacity by user connected.

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1.3 μm p-Modulation Doped InGaAs/GaAs Quantum Dot Lasers with High Speed Direct Modulation Rate and Strong Optical Feedback Resistance

Crystals ◽

10.3390/cryst10110980 ◽

2020 ◽

Vol 10 (11) ◽

pp. 980

Author(s):

Xia-Yida MaXueer ◽

Yi-Ming He ◽

Zun-Ren Lv ◽

Zhong-Kai Zhang ◽

Hong-Yu Chai ◽

...

Keyword(s):

Quantum Dot ◽

High Speed ◽

Optical Feedback ◽

Maximum Output Power ◽

Threshold Current ◽

Maximum Output ◽

Large Signal ◽

Direct Modulation ◽

Modulation Rate ◽

Gaas Quantum Dot

Aiming to realize high-speed optical transmitters for isolator-free telecommunication systems, 1.3 μm p-modulation doped InGaAs/GaAs quantum dot (QD) lasers with a 400 μm long cavity have been reported. Compared with the un-doped QD laser as a reference, the p-doped QD laser emits at ground state, with an ultra-low threshold current and a high maximum output power. The p-doped QD laser also shows enhanced dynamic characteristics, with a 10 Gb/s large-signal direct modulation rate and a 7.8 GHz 3dB-bandwidth. In addition, the p-doped QD laser exhibits a strong coherent optical feedback resistance, which might be beyond −9 dB.

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Devices, communication techniques and networks for all optical communication: research issues

Journal of Optical Communications ◽

10.1515/joc-2020-0276 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Vikas Kaushik ◽

Himanshi Saini

Keyword(s):

Optical Networks ◽

Communication Networks ◽

Optical Communication ◽

High Speed ◽

Research Issues ◽

Communication Techniques ◽

Communication Technique ◽

All Optical ◽

High Speed Data ◽

Further Development

Abstract The characteristics of all optical networks such as high speed, data carrying capacity and transparency make them suitable for emerged networks domain. This paper presents an overview of research challenges in the field of all optical communication networks. Various subdomains of an all optical system, for example device-level designs, communication technique-level designs and network-level designs have been extensively investigated and presented in this paper. Further, the related research issues under each category of these domains have been discussed. These issues constitute the basic criterion for further development in all optical domain.

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Up conversion and excited state absorption analysis in the Tm:YAG disk laser multi-pass pumped by 1 μm laser

High Power Laser Science and Engineering ◽

10.1017/hpl.2020.55 ◽

2021 ◽

Vol 9 ◽

Author(s):

Enmao Song ◽

Guangzhi Zhu ◽

Hailin Wang ◽

Hantian Chen ◽

Yefeng Qian ◽

...

Keyword(s):

Excited State ◽

Pump Power ◽

Radiative Decay ◽

Beam Quality ◽

Maximum Output Power ◽

Excited State Absorption ◽

Stimulated Emission ◽

Maximum Output ◽

Disk Laser

Abstract We present a 2 μm Tm:YAG disk laser multi-pass pumped by a 1 μm laser. The transitions in competition of up conversion (UC) and excited state absorption (ESA) are analyzed in detail based on a numerical model that considers stimulated emission, fluorescence, non-radiative decay, UC, andESA, showing good agreement with experiments. The proportions and fractional thermal loads of all transitions are derived quantitatively. The results show that UC and ESA are critical in Tm:YAG disk lasers, resulting in a decrease in the absorbed pump power and temperature after lasing for two different disk thicknesses. In addition, although the absorbed pump power of the 0.5 mm disk is lower than in the 1 mm case, its relatively weak UC and ESA and low total fractional thermal load can improve laser performance. A 0.5 mm Tm:YAG disk laser thus delivered the maximum output power of1.05 W with beam quality of Mx2 = 2.02 and My2 = 2.03.

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Compensation of Interpolation Error for Look-Up Table-Based PMSM Control Method in Maximum Power Control

Energies ◽

10.3390/en14175526 ◽

2021 ◽

Vol 14 (17) ◽

pp. 5526

Author(s):

Do-Yun Kim ◽

Jung-Hyo Lee

Keyword(s):

Control System ◽

Power Control ◽

High Speed ◽

Maximum Output Power ◽

Compensation Method ◽

Maximum Power ◽

Torque Control ◽

Interpolation Error ◽

Maximum Output ◽

Look Up Table

This paper proposes a compensation method for interpolation error of the maximum power control of a PMSM control system that generates current commands through a look-up table. A torque control system using a look-up table created through experiments has superior characteristics, such as control stability and torque accuracy, compared to a system that executes torque control via a linear controller based on modeling. However, it is impossible to generate information on all the currents for the output torque in the table. Therefore, because the data stored in the look-up table have a discrete characteristic, they are linearly interpolated to generate a current command for the torque command. However, the PMSM current trajectory is generally elliptical, which causes an error owing to linear interpolation, reducing the maximum output power. In particular, when the table data are insufficient, such as in the high-speed operation range, the reduced maximum output cannot be ignored. This paper proposes a compensation method for the interpolation error using two feedforward compensators and a PI controller, which was verified through experiments.

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Cladding-Pumped Erbium/Ytterbium Co-Doped Fiber Amplifier for C-Band Operation in Optical Networks

Applied Sciences ◽

10.3390/app11041702 ◽

2021 ◽

Vol 11 (4) ◽

pp. 1702 ◽

Cited By ~ 1

Author(s):

Andis Supe ◽

Sergejs Olonkins ◽

Aleksejs Udalcovs ◽

Ugis Senkans ◽

Rihards Mūrnieks ◽

...

Keyword(s):

Optical Networks ◽

Noise Figure ◽

Maximum Output Power ◽

Optical Power ◽

Wavelength Dependence ◽

Fiber Amplifier ◽

System Level ◽

Maximum Output ◽

Saturation Regime ◽

Co Doped

Space-division multiplexing (SDM) attracts attention to cladding-pumped optical amplifiers, but they suffer from a low pump power conversion efficiency. To address this issue, ytterbium (Yb3+) and erbium (Er3+) co-doping is considered as an effective approach. However, it changes the gain profile of Er3+-doped fiber amplifiers and induces the gain difference between optical wavelengths in the C-band, significantly limiting the effective band of the dense wavelength-division multiplexed (DWDM) system. This paper is devoted to a detailed study of a cladding-pumped Er3+/Yb3+ co-doped fiber amplifier (EYDFA) through numerical simulations aiming to identify a configuration, before assembling a similar EYDFA in our laboratory premises that ensures the desired performance. The simulation model is based on a commercial double cladding EYDF whose parameters are experimentally extracted and fed to the EYDFA setup for the system-level studies. We investigate the wavelength dependence of the amplifier’s characteristics (absolute gain, gain uniformity, noise figure) and bit error rate (BER) performance for several DWDM channels and their optical power. The obtained results show that a 7 m long EYDF and co-propagating pump direction is preferable for the EYDFA with a 3 W pump source at 975 nm and with the given gain medium characteristics for WDM applications. For instance, it ensures a gain of 19.7–28.3 dB and a noise figure of 3.7–4.2 dB when amplifying 40 DWDM channels with the input power of −20 dBm per channel. Besides, we study EYDFA gain bandwidth and the maximum output power when operating close to the saturation regime and perform a sensitivity analysis showing how the doped fiber’s absorption and emission cross-sections impact the amplification process through energy transfer from Yb3+ to Er3+. Finally, we quantify the power penalty introduced by the EYDFA; the results show that it is not higher than 0.1 dB when amplifying 40 × 10 Gbps non-return-to-zero on-off keying signals from −20 dBm/channel.

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Intellectual method of operational evaluation of the network element state to ensure the quality of services in corporate multiservice communications networks

E3S Web of Conferences ◽

10.1051/e3sconf/202020305017 ◽

2020 ◽

Vol 203 ◽

pp. 05017

Author(s):

Sergey Ageev ◽

Vladimir Karetnikov ◽

Evgeny Olkhovik ◽

Privalov Andrey

Keyword(s):

Real Time ◽

Communication Networks ◽

Intelligent Agents ◽

High Speed ◽

Optimization Problems ◽

The State ◽

Main Task ◽

Communication Services ◽

High Dynamics

The work proposes and investigates an intelligent method and algorithms for on-line assessment of the state of network elements to ensure the required quality indicators of provided communication services in corporate high-speed multiservice communication networks. The developed method and algorithms operate in a mode close to real time. One of the features of corporate multiservice communication networks is the high dynamics of changes in their state. The main task of the automated control system, which is an integral part of the corporate multiservice communication network, is to ensure the specified quality of the provided communication services to the consumer. Thus, the relevance of the research presented in the work is due to the fact that most of the management processes in corporate high-speed multiservice communication networks must be implemented in a mode close to real time with a given quality. The basis of the method for operational assessment of the state of network elements is the concept of creating and using intelligent agents. In the proposed approach, intelligent agents are created as hierarchical fuzzy situational networks, in which control solutions, in contrast to known methods based on the use of reference situations, are applied based on solving a hierarchical set of optimization problems using fuzzy mathematical programming methods. The main paradigm of their functioning is “situation -action”.

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