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In this paper, we have designed and presented a simulation analysis of 96 × 40 Gbps CSRZ based DWDM long-haul transmission system under the influence of Kerr non-linearities using hybrid dispersion compensation technique. The proposed system performance is measured at 50 GHz channel spacing in terms of BER, Q-factor and eye-diagram for the varied launched power ranging from −4 dB m to 12 dB m of CW laser array and various transmission distances. We have implemented pre-filtering before multiplexing the modulated data of all the channels and post-filtering after de-multiplexing for avoiding co-channel interference and to suppress the cross-talk. By optimizing the system parameters, the transmission distance of 16,500 km is achieved for BER value of 1.48,875E-14 with corresponding Q-factor value of 7.55,989 at 6 dB m input power. The CSRZ modulated system has shown much robustness against the occurred linear and non-linear degradation factors due to its narrow spectrum. [ABSTRACT FROM AUTHOR]

Abstract Free space optical (FSO) systems offer an attractive and cost-effective solution for providing communication services in remote regions, as they allow secure transmission without the need for licensing and with lower deployment costs. However, the performance of FSO systems can be significantly impacted by atmospheric turbulences, creating considerable challenges to their deployment. To meet the expanding bandwidth requirements in optical networks, dense wavelength division multiplexing (DWDM) has emerged as a viable option. The development of a 400-Gbps DWDM-FSO system with advanced modulation formats is the subject of this paper. To ensure efficient energy conservation in such a system, power consumption needs to be minimized while maintaining performance level; this calls for optimization of different components within the system. The system is made up of 10 channels and each channel can transmit data at 40 Gbps. Various modulation schemes like carrier-suppressed return-to-zero, modified duo binary return-to-zero, differential phase shift keying, and duo binary return-to-zero are studied for their impact on system performance parameters Q-factor and bit error rate (BER) in C-band around 1550 nm wavelengths. The assessment is also extended to the effects that changing FSO length, input power, and data rate have on these two parameters as well as an evaluation regarding how differing atmospheric conditions influence the FSO system’s effectiveness.

Free space optical (FSO) systems offer an attractive and cost-effective solution for providing communication services in remote regions, as they allow secure transmission without the need for licensing and with lower deployment costs. However, the performance of FSO systems can be significantly impacted by atmospheric turbulences, creating considerable challenges to their deployment. To meet the expanding bandwidth requirements in optical networks, dense wavelength division multiplexing (DWDM) has emerged as a viable option. The development of a 400-Gbps DWDM-FSO system with advanced modulation formats is the subject of this paper. To ensure efficient energy conservation in such a system, power consumption needs to be minimized while maintaining performance level; this calls for optimization of different components within the system. The system is made up of 10 channels and each channel can transmit data at 40 Gbps. Various modulation schemes like carrier-suppressed return-to-zero, modified duo binary return-to-zero, differential phase shift keying, and duo binary return-to-zero are studied for their impact on system performance parameters Q-factor and bit error rate (BER) in C-band around 1550 nm wavelengths. The assessment is also extended to the effects that changing FSO length, input power, and data rate have on these two parameters as well as an evaluation regarding how differing atmospheric conditions influence the FSO system's effectiveness. [ABSTRACT FROM AUTHOR]

Free space optical (FSO) communication reduces the last-mile bottleneck problem wherever we cannot use fiber-optic links. Performance degradation in the FSO system is mainly due to the atmospheric turbulence effect. To increase the capacity of the system wavelength division multiplexing (WDM) is used. An experimental testbed is set up to investigate the performance of the DWDM-FSO system with and without crosstalk under the influence of atmospheric turbulence. For the study of the system performance, the attenuation values due to scintillation from the existing work are taken as losses. Based on the results, the FSO link length that supports the data transmission is up to 3 km for the tolerable BER of 10−9. The Q-factor value drops with increasing attenuation and link distance. Q value of the FSO system without crosstalk and with crosstalk at 2 dB is 10.64 and 6.34 for 1 km and 4 km, it is 7.94 and 4.24 respectively. [ABSTRACT FROM AUTHOR]

We propose a Dense Wavelength Division Multiplexing (DWDM) Demultiplexer for L band (1565–1635 nm) applications. The design comprises a Y-shaped branch, a circular ring cavity (CRC), a bus waveguide, and a drop waveguide. To simplify the fabrication process, a CRC cavity is used instead of a regular large ring resonator in the design. The diameter of the CRC cavity is 820 nm. Coupled mode theory is used to examine the behaviour of the proposed demultiplexer. Proposed design achieves a narrow resonant wavelength of 12.5 GHz with a 0.1 nm spectral linewidth, a high-quality factor of 15,789, and minimal cross-talk of − 85 dB between adjacent channels. The results confirm that there is a transmission peak at one of the output port, with simultaneous drop of transmission power i.e. zero, at other output port. Additionally, the results convey that the reflection is zero at the peak resonant wavelength for all channels. Further, the proposed design offers a fabrication tolerance of ± 1 nm for air hole and CRC radii at which the resonant wavelength and transmission would not be effected. [ABSTRACT FROM AUTHOR]

The current paper aims to explore the dynamics of optical solitons in the presence of multiplicative white noise within a DWDM topology. The utilization of Jacobi's elliptic function and Itô Calculus has made it possible to retrieve the soliton solutions. The presence of white noise has an exclusive effect on the phase component of the solitons. [ABSTRACT FROM AUTHOR]

This paper presents a 4-channel demultiplexer totally based on a two-dimensional photonic crystal with silicon air holes and defects with the advent of a graphene sheet, in multiplexing systems that use Dense Wavelength Division Multiplexing. Methods that incorporate Plane Wave Expansion and finite difference time domain are used, as they have significant efficiency to generate the photonic hollow modes of the demultiplexer and analyze the global distribution and transmission, respectively. Parameters of transmission overall performance, maximum quality factor, spectral width, crosstalk, and channel spacing of the demultiplexer are very important statistics to confirm the overall performance of the device, whose values are about 92%, 1944.3, 0.9 nm, − 60 dB and 0.1 nm, respectively, whose consequences are problem to the validation of the requirements of the Dense Wavelength Division Multiplexing device (ITU.G.694.1). The proposed demultiplexer includes a bus or linear waveguide with graphene to guide the slight wave and 4 resonant cavities wherein graphene is placed withinside the center to select out the wavelength in a hexagonal lattice form of dielectric air holes in air. The bus waveguide transmits slight into the resonant hole area and exits through the respective falling waveguide. [ABSTRACT FROM AUTHOR]

A new disintegrated channelization approach for the backward pumped nonlinear distributed Raman amplifier is proposed by enacting the differential coupled equations of Raman amplification, in fiber, trailing by the solution of NLSE using the first integral method first time to the best of our knowledge. A nonlinear channel modeling-based simulation is adapted for the approximation of the Raman gain profile. To realize the real-time dynamic system, 16 multiplexed channels of prime C-band are employed in a QPSK/NRZ modulation environment with a 100 Gbps bit rate for optical network reconfiguration. A non-uniform gain is reported while the disparity in BER is observed from 10−12 to 10−8. [ABSTRACT FROM AUTHOR]

In this study, a new four channel de-multiplexer with a ring resonator design is proposed. The bus waveguide and drop waveguide that make up the Ring Resonator are ring-shaped. In the proposed four channel demultiplexer design, one bus waveguide and four drop waveguides were built using a photonic crystal ring resonator. To improve output efficiency, the proposed demultiplexer was built with distinct inner radius values for each channel. With the resonance wavelengths for each channel in the range of 1552.4 nm, 1553.2 nm, 1554.1 nm, and 1555.4 nm, the suggested demultiplexer average quality factor was 7870.90, and its average transmission efficiency was 98.67%. The demultiplexer was created with a 0.8 nm narrow channel spacing with a − 15 dB to − 25 dB crosstalk range. The proposed ring resonator structure is made of silicon, which has a refractive index of 3.47, a center wavelength ranges of 1550 nm, and a lattice constant that varies with the radius range of 540 nm. To examine the performance, one can simulate the suggested demultiplexer structure using the FDTD (Finite-Difference Time-Domain) approach. The proposed work 198.7 µm2 footprint is appropriate for DWDM applications. [ABSTRACT FROM AUTHOR]

Free space optical (FSO) systems offer a desirable and affordable way of providing communication services in remote locations. They provide secure wireless transmission without the requirement for licensing and with lower implementation costs. However, due to the impact of atmospheric turbulences on the effectiveness of FSO systems, their implementation faces significant challenges. Dense wavelength division multiplexing (DWDM) has shown promise in addressing the growing bandwidth needs in optical networks. This paper introduces a hybrid optical amplifier based system, combining DWDM and FSO technology. Energy conservation in such a system involves optimizing various aspects to reduce power consumption while maintaining or improving performance. The proposed DWDM-FSO system operates at a rate of 480 Gbps and consists of 12 channels, each capable of transmitting data at 40 Gbps. The system's performance is evaluated and compared by determining the Q-factor and bit error rate (BER) for both the cases when hybrid amplifier is employed and with no hybrid amplifier within the C-band, specifically focusing on wavelengths around 1550 nm. Moreover, the length of the FSO link is increased to assess the corresponding Q-factor and BER. Resultantly, the maximum distance for the FSO link is determined, ensuring that it remains within acceptable Q-factor and BER thresholds. Furthermore, the FSO system's effectiveness is assessed and compared across various atmospheric conditions. The findings reveal that, in clear weather conditions, the FSO system achieves a maximum distance of 510 meters while maintaining satisfactory Q-factor and BER values when not utilizing a hybrid amplifier. However, by integrating a hybrid amplifier, the system's reach significantly extends to 1700 m under clear weather conditions, still maintaining acceptable Q-factor and BER values.

This review paper scrutinizes the staging of dense wavelength division multiplexing soliton system in return to zero and non-return to zero format. In-line optical phase conjugator (OPC) is used to depreciate the power of four wave mixing (FWM). Destructive interference between both the halves of in-line OPC plummets the FWM power sturdily. This paper concludes with the indication that return-to-zero with OPC gives out better performance with FWM suppression. [ABSTRACT FROM AUTHOR]

In this paper, we develop a novel demultiplexer design for Coarse Wavelength Division Multiplexer (CWDM). The device consists of multi-layer inhomogeneous semi-conductor material, where the refractive index of each layer is graded according to a predefined profile. The proposed design exploits the ray's spatial shift that results from the material dispersion as different wavelengths propagate through the different layers of the device. Our design forces the multiplexed light to refract after propagation for short distance within the device leading to smaller device size while providing the needed spatial shift between the ray's of the adjacent multiplexed wavelengths. The proposed structure can be easily implemented using the well-established technology utilized in fabricating existing graded-index fibers. The impacts of the various design parameters (such as the incident angle, number of layers, the layer thickness, the spacing between adjacent wavelengths, the refractive index difference) on the amount of achieved spatial shift between the adjacent wavelengths and the size of the device are investigated. Compared to previous proposed techniques, our device can be easily fabricated to provide higher spatial shift while reducing the device size with by controlling the different design parameters. [ABSTRACT FROM AUTHOR]

Nonlinear impacts arising from Kerr effect cause crucial limitations in the performance of optical communication systems. The combined impact of SPM, XPM and FWM in WDM-based communication systems has rarely been focused on with experimental or numerical methods because of complicated nature of optical nonlinear phenomena, modeling complexity, limitations on testing equipment and difficulties in performing measurements over long distances. Furthermore, in limited number of papers concentrating on the combined impact of SPM, XPM and FWM in WDM-based systems, total impact has generally been determined by summation of results obtained from individual impacts of SPM, XPM and FWM. Thus, the interplay among SPM, XPM and FWM has often been neglected. In this paper, the combined impact of SPM, XPM and FWM in DWDM long-haul communication systems has been modeled and computationally analyzed. Variations of signal-to-crosstalk ratio (SXR) with input powers of channels and channel spacings under the combined impact of SPM, XPM and FWM and the single impact of FWM have been observed and compared. Comparison of research results with results of former studies has also been presented. Research results show that combined impact of SPM, XPM and FWM is significant below 100 GHz channel spacings for input powers of 3 mW and 5 mW, below 50 GHz channel spacings for 1 mW input powers and below 30 GHz channel spacings for 0.5 mW input powers. For input powers of 0.1 mW, instead of the combined impact of SPM, XPM and FWM, single impact of FWM can be considered. [ABSTRACT FROM AUTHOR]

Hollow-core optical fibers (HCFs) have unique properties like low latency, negligible optical nonlinearity, wide low-loss spectrum, up to 2100 nm, the ability to carry high power, and potentially lower loss then solid-core single-mode fibers (SMFs). These features make them very promising for communication networks and similar applications. However, this class of fibers is still in development. Current applications are almost exclusively limited to low-latency data links for High-Speed Trading (HST); other uses are in the trial stage now. In this paper, we comprehensively review the progress in the development of HCFs including fiber design, fabrication and parameters (with comparisons to conventional single-mode fibers) and support technologies like splicing and testing. A variety of HCF applications in future telecom networks and systems is analyzed, pointing out their strengths and limitations. Additionally, we review the influence of filler gas and entry of contaminants on HCF attenuation, and propose a new fusion splicing technique, avoiding the destruction of the fiber's photonic cladding at high temperature. [ABSTRACT FROM AUTHOR]

Gain flatness of erbium-doped fiber amplifier (EDFA) is an important aspect to support high speed multimedia applications for smart devices, cloud computing, big data analysis and high definition television (HDTV) as it achieves equal power for all dense wavelength division multiplexing (DWDM) channels. In this paper, we compare 32 and 64 channels 10 Gbps DWDM system using hybrid EDFA+ Ytterbium-doped silica fiber amplifier (YDFA) in C + L band for 0.4, 0.8 and 1.6 nm wavelength spacing along with FBG for gain flattening. The system performance has been analyzed in terms of optical signal to noise ratio and spectral gain fluctuation observed from the optical power spectrums. It is observed that YDFA although extends the amplification window of EDFA from 1530 to 1610 nm (C to L band), but gain fluctuates over the operating wavelength range. Gain flatness is enormously improved (5–10 dB) by adding FBG as a gain flattening filter to the hybrid (EDFA+YDFA) amplifier. It is found that as the channel spacing decreases (from 1.6 to 0.4 nm) and the number of channels increases (from 32 to 64), the gain reduces due to inter-channel crosstalk and four wave-mixing effect. [ABSTRACT FROM AUTHOR]

This article investigates a secure reliable dense-wavelength-division-multiplexing (DWDM) with three different kinds of media for many geographic environments. A 80 Gb/s data transmission at Ka band (28 GHz) based three secure physical links using an optical chaotic signal, which applies a mask to hide the transmitted signal inside a generated chaos sketch. Based to the achieved results, the chaotic signal has a considerable effect on the free space optics than fiber optics. The simulation findings depict that the new model has an acceptance performance for all simulated links with 10-34 BER in the case of 4x4 FSO, but the ratio is degraded to 10-5 with increasing the distance of 3 Km. Similarly, the BERs are decreased from 10-32 to 10-8 when the coarse-DWM optical fiber is utilized; In the case of cascaded SMF-4x4 FSO, BER ratio is declined from 10-32 to 10-6. The proposed model has a best quality compared with the former chaotic studies and investigations.

The manuscript presents detailed investigation of dense wavelength-division multiplexing (DWDM)-oriented intersatellite optical wireless network. Total 48 channels are transmitted at 40 Gbps through open space over distance of 3 km. Apart from that, two modulators Mach Zehnder (MZM) and electro-absorption (EAM) are also deployed to estimate their performance. It is reported that DWDM network gives best output when maximum number of channels are accommodated around 1550 nm over distance of 2 km along with use of MZM. The bit error rate (BER), electrical power and eye diagram are used as parameters to analyze the output. [ABSTRACT FROM AUTHOR]

This study offers the most recent network architecture employing the CWDM/DWDM/5G millimeter wave system over the Free-Space Optical Communication (or FSOC) channel with performance analysis of the Refractive Index Structural Parameter (or RISP), from weak turbulence 10 - 20 m−2/3 to strong turbulence 10 - 10 m−2/3. The hybrid CWDM/DWDM system and the 5G millimeter Wave (or mm Wave) transmission technology are the two major components that the proposed system would unite under a single FSOC channel. To assess the effectiveness of the proposed system at 500 m transmission data distance, the Min Bit Error Rate (or BER), the Max Q-factor, the Received Electrical Signal Power (or RESP), the Received signal-to-noise ratio (or RSNR), the Communication Capacity (or CC), and the Total Communication Capacity (or TCC) are investigated. The effectiveness analysis of the proposed system indicates that the FSOC transmission channel may be impacted by the RISP variance, which may lead to a decline in system performance. To get around this, the receiver side of the proposed system performs better thanks to the usage of the SQuare RooT (or SQRT) and Electrical Rescale (or ER) blocks. However, to correct the photodiode's square law characteristics and enhance the received signal quality, the SQRT block has been used. Moreover, the ER block has been included to scale the electrical signal input's minimum and maximum values to those previously set in the electrical pulse generator. The results of the simulation are successful, particularly when the SQRT and ER blocks are incorporated into the suggested system. For each result, the predicted RISP value and the estimated RESP, RSNR, CC, and TCC values have been achieved for the tolerable Min BER and Max Q-factor values of approximately 1e-09 and 6, respectively. [ABSTRACT FROM AUTHOR]

The hybrid radio over fiber (RoF) and polarization division multiplexed (PDM) networks are indispensable to satisfy the exigencies of 5th-generation (5G) networks. In this work, an ultra-high-capacity dense wavelength division multiplexed (DWDM) RoF system is presented over 80 km using PDM-128-quadrature amplitude modulation (QAM), digital signal processing (DSP), and matched filters. Three different scenarios are considered in this work such as (1) an integrated 16-channel DWDM and 40 GHz RF-enabled RoF system (2) an integrated 16-channel DWDM and 24 GHz RF-enabled RoF system, and (3) an integrated 8-channel DWDM and 40 GHz RF-enabled RoF system. The results are analyzed in terms of error vector magnitude percentage (EVM%), log symbol error rate (SER), quality (Q) factor, signal-to-noise ratio (SNR), and bit error rate (BER). Further, the effects of the DSP on system performance are explored, and a performance comparison of existing single polarization (SP)-QAM and dual polarization (DP)-QAM is also established. [ABSTRACT FROM AUTHOR]

Metro-access networks will play a primary role in future network fabrics, enabling connectivity among different actors such as 5G-based radio stations, edge datacenters, businesses, and home users. To provide such heterogeneous connectivity, changes to the current metro-access networks to provide them with greater scalability, higher levels of dynamic connectivity and flexibility, reduced end-to-end latency, and increased energy efficiency are required. In this context, mesh-based ultra-dense wavelength division multiplexing (u-DWDM) metro-access networks using reconfigurable optical switching nodes constitute a promising solution. However, the designs of traditional optical switching nodes are based on wavelength selective switches (WSSs), which provide high network reconfigurability only at a high cost, making them prohibitive for metro-access networks. Moving away from this design approach, a novel cost-effective and energy-efficient reconfigurable optical add-drop multiplexer (ROADM) node design built using a modular DWDM structure was recently proposed for ring-based u-DWDM metro-access networks, showing promising performance. This paper presents an optical node design for optical cross-connects (OXCs) utilizing a modular DWDM structure, with the objective of providing performance close to that of WSS-based OXCs but at a lower cost. With this target in mind, the optimal design of mesh-based u-DWDM metro-access networks was also studied using DWDM OXCs and ROADMs, with the aim of maximizing the network throughput while minimizing the hardware required to implement the switching nodes. To this end, both exact and heuristic mechanisms are presented to address the optimal network design. The results show a maximum network performance reduction of just 10% in the DWDM case compared to the WSS-based case with a switching node cost reduction in one order magnitude. [ABSTRACT FROM AUTHOR]

Wireless networks have recently required the development of a backbone system with high bandwidth capacity and optical fiber transmission over long distances as well. Therefore, coherent optical technology provides broadband communications with advanced modulation techniques to meet the requirements of wireless networks, such as the fifth-generation 5G system. In this paper, the Dual Polarization-M-Quadrature Amplitude Modulation (DP-M-QAM) levels have been integrated with the Dense Wavelength Division Multiplexing (DWDM) technique. The system focuses on high data transmission over long-haul optical fiber with digital signal processing (DSP) treatment in the receiving section. The transmission of 100 Gbits/s, × 16 channels has been achieved using Single Mode Fiber (SMF) over lengths from 80 to 320 km, and channel spacing up to 100 GHz. The DP-M-QAM modulation levels based on coherent DWDM simulation were evaluated using the Optical Signal-to-Noise Ratio (OSNR) parameter. The performance of the proposed model is evaluated and analysed in terms of different results of Bit Error Rate (BER) and Error Vector Magnitude (EVM). Compared to already existing solutions, our system demonstrates the best compromise in terms of the number of channels, the long transmission distance of up to 300 km and also minimum BER, which makes it an efficient solution. The proposed transmission provides a DSP subsystem to support a broader range of DP-MQAM modulation formats for high-speed wireless communication networks. [ABSTRACT FROM AUTHOR]

This paper proposed three different Raman optical amplifier architectures that are designed and investigated for 50 × 100 Gbps dense wavelength division multiplexed (DWDM) system at channel spacing of 0.8 nm. The performance is determined and compared in terms of gain, gain ripple, noise figure (NF), Q-factor and bit error rate (BER) in the C-band at wavelengths in the vicinity of 1550 nm. Pump powers of the Raman amplifier are selected using multiparameter optimization algorithm to achieve maximum gain with small ripple. The effects of varying input powers on gain, gain ripple and NF are also investigated. Raman amplifier with bidirectional pumping configuration achieves highest average gain of 21.42 dB with lowest gain ripple of 1.24 dB. Average gain of 21.37 dB with gain ripple of 1.55 dB is obtained for forward pumping configuration. For backward pumping configuration, an average gain of 21.32 dB is obtained. All three configurations achieved a good quality factor (> 12.0 dB) at each wavelength. The utility of these Raman optical amplifier architectures in long-distance DWDM systems is validated by the obtained high gain, improved gain flatness, good Q-factor, and low BER. [ABSTRACT FROM AUTHOR]

This paper proposes an ultra-high capacity free space optical communication (FSO) system, employing optical dual polarization quadrature phase shift keying (DP-QPSK) modulation format. It is a 16-channel dense wavelength division multiplexing (DWDM) system with 120 Gbps/channel bit rate. The FSO system is analyzed with three optical advanced modulation schemes; such as 4-quadrature amplitude modulation (4-QAM), quadrature phase shift keying (QPSK) and DP-QPSK. The main focus of the projected system is to improve the FSO setup performance in terms of eye diagram, bit error rate (BER), high received power and Q-factor. The center channel wavelength used for the proposed system is 1550 nm. In the present wireless communication world, the proposed system will be highly helpful as an ultrahigh capacity wireless system. [ABSTRACT FROM AUTHOR]

In this paper, a competent flat gain hybrid optical amplifier is proposed with an optimum arrangement of erbium doped fiber amplifier (EDFA) and Raman amplifier. Attempts are made to design a hybrid optical amplifier for100 channels, 10 Gbps super dense wavelength division multiplexed (SDWDM) systems at channel spacing of 0.1 nm. Work capacity of the system was compared on the basis of various parameters, viz., noise figure and gain that determined the performance of the system. The gain spectrum of the hybrid optical amplifier depends upon the parameters viz., laser input power, pump power and pump wavelength of the amplifier. It was found that for wavelength range 1,560.38–1,579.59 nm, a flat gain of 4.34 dB is achieved for input power of −10 dB with noise figure variation of 0.818 dB without using any gain flattering scheme. Being simple and cost effective, this hybrid optical amplifier could be recommended for gain flatness characteristics and acceptable noise figure for dense wavelength multiplexed systems. [ABSTRACT FROM AUTHOR]

Large capacity optical networks require flattened gain spectrum and large gain bandwidth of the optical networks. In order to achieve this large number of hybrid optical amplifiers are designed. Here we proposed a competent flat gain hybrid optical amplifier with an optimum combination of Erbium Doped Fiber Amplifier (EDFA) and Raman amplifier. Attempts are made to design a hybrid optical amplifier for 100 channels, 10 Gbps Super Dense Wavelength Division Multiplexed (SDWDM) systems at different channel spacing of 0.1, 0.2, 0.4 and 0.8 nm. Work capacity of the network was compared on the basis of various parameters viz., gain and noise figure that determined the performance of the system. The gain spectrum of the hybrid optical amplifier depends upon the parameters viz., pump wavelength, pump power and laser input power of the amplifier. Various efforts were conceded out to optimize these parameters. It was found that for wavelength range 1,570.5–1,580.75 nm, a flat gain of 5.36 dB is achieved for input power of −15 dB with noise figure variation of 0.57 dB without using any gain flattering scheme. Being simple and cost effective, this hybrid optical amplifier could be recommended for gain flatness characteristics and acceptable noise figure for super dense wavelength division multiplexed system. [ABSTRACT FROM AUTHOR]

The quality of service (QoS) is an important and considerable issue in designing survivable dense wavelength division multiplexing (DWDM) backbones for IP networks. This paper investigates the effect of network topology on QoS delivering in survivable DWDM optical transport networks using bandwidth/load ratio and design flexibility metrics. The dedicated path protection architecture is employed to establish diverse working and spare lightpaths between each node pair in demand matrix for covering a single link failure model. The simulation results, obtained for the Pan-European and ARPA2 test bench networks, demonstrate that the network topology has a great influence on QoS delivering by network at optical layer for different applications. The Pan-European network, a more connected network, displays better performance than ARPA2 network for both bandwidth/load ratio and design flexibility metrics.

Design of fault tolerant dense wavelength division multiplexing (DWDM) backbones is a major issue for service provision in the presence of failures. The problem is an NP-hard problem. This paper presents a genetic algorithm based approach for designing fault tolerant DWDM optical networks in the presence of a single link failure. The working and spare lightpaths are encoded into variable length chromosomes. Then the best lightpaths are found by use of a fitness function and these are assigned the minimum number of wavelengths according to the problem constraints using first-fit (FF) algorithm. The proposed approach has been evaluated for dedicated path protection architecture. The results, obtained from the ARPA2 test bench network, show that the method is well suited to tackling this complex and multi-constraint problem.

In this article, the proposed Distributed Raman Amplifier (DRA) simulator is designed on the MATLAB Simulink platform. 16 channels DWDM in C-band (1544–1559 nm) and 32 channels CWDM system in S-, C- and L band (1460–1625 nm) are executed with data rate of 100 Gb/s. The designed standalone system realizes the various effects that may arise at the receiver output due to reconfiguration of channels in real-time dynamic WDM optical traffic. Gain excursion assessment, and bit error rate (BER) are investigated for 200 km long Fiber cable and 45 km of Raman amplifier in co-pumping, counter pumping and bidirectional pumping propagation. [ABSTRACT FROM AUTHOR]

The fiber-optic communication lines and fiber-optic transmission systems using fiber-optic cable, receiving and transmitting optical modules based on WDM and DWDM (Wavelength Division Multiplexing & Dense WDM) technologies are studied. A method for calculating the transmission characteristics fiber-optic communication lines is proposed and relationships are obtained that establish an analytical relationship between the length regeneration section and the transmission rate. This paper discusses the study and analysis indicators fiber-optic communication lines using spectral WDM and DWDM technologies.

A novel promoted parallel erbium doped fiber amplifier (PP-EDFA) is numerically demonstrated and investigated, for high capacity 95 × 40 Gb/s dense wavelength division multiplexing (DWDM) transmission system. The proposed PP-EDFA is used to achieve a flat gain over wideband within communication window. The amplifier consists of two sections of erbium-doped fiber (EDF) with a total length of 6 m and requires a total pump laser power of 195 mW. The results reveal that the amplifier has flat gain of 19.8 dB with a ripple of less than 1 dB, over broad bandwidth of 80 nm. The noise figure (NF) of proposed amplifier fluctuates between 3.1 and 5.2 dB, within bandwidth of 1520–1600 nm. In contrast with parallel EDFA (P-EDFA), the proposed PP-EDFA contributes to a higher and flatter gain, as well as it requires shorter EDFs and lower pumping power. The acceptable bit error rate (BER) and signal quality results prove the feasibility of proposed PP-EDFA for applications in broadband DWDM transmission systems. The PP-EDFA can achieve a maximum transmission distance of 90 km for 95-channel DWDM transmission system. [ABSTRACT FROM AUTHOR]

In optical fiber communications, data travels from the transmitter to the receiver, where it is collected and converted from optical pulses into electrical signals. The need for bandwidth has grown significantly in recent years. Dense Wavelength Division Multiplexing (DWDM), an advanced multiplexing technology that allows multiple signals to be delivered simultaneously at different wavelengths in the same channel, has been developed to meet the demand for higher capacity and faster data rates. There is a decrease in signal quality as a result of the pulse expansion caused by the scattering. During long-distance transportation, scattering should be minimized. In this research, The DWDM link model uses OptiSystem 18. The DWDM design uses 48 channels, 200 GHz channel spacing, and a bit rate of 40 Gbps for each channel The link length used is 240 and 300 km, using SMF (Single Fiber Mode) and DCF (Dispersion Compensation Amplifier). The research was performed with differences in laser power of 0, 3, and 5 dBm. From the results of the analysis carried out, changes in power changes affect the performance of the system using the MRZ (Mach Zander rate) produced by a CW-10 dB laser. The laser power values correspond to the standard Q-factor and BER (Bit Error Rate) values. The highest Qfactor is 23.266 and BER is 4.66232e-0120, while the lowest Q-factor is 14.9477 and BER is 7.89923e-051. Research has shown The more laser power is used, the better the system's performance. [ABSTRACT FROM AUTHOR]

In this paper, two models of fiber-to-the-x (FTTx) networks are provided, one of hybrid dense wavelength division multiplexing/coarse wavelength division multiplexing (DWDM/CWDM) with high subscriber's allocated bandwidth, and the other of hybrid ultra-dense wavelength division multiplexing/coarse wavelength division multiplexing (UDWDM/CWDM) with high network capacity. The effect of the fiber chromatic dispersion on the signal quality was demonstrated. The behavior of the network with respect to the changing of the DWDM channel spacing and the relation between the channel spacing and the system bit rate was discussed. [ABSTRACT FROM AUTHOR]