Dense Wavelength Division Multiplexing Systems Research Articles

Optimizing High Data Rate Up to 2.5 Tbps Transmission using 64-Channel DWDM System with DCF and NRZ Modulation

Objectives: This study aims to enhance and optimize a modern communication system for high data rate transmission using Dense Wavelength Division Multiplexing (DWDM). The objectives include employing a 64-channel DWDM system, implementing different data speeds, and utilizing a dispersion compensation method. Methods: To achieve the objectives, we simulate and analyze the effects of Dispersion Compensation Fiber (DCF) in a DWDM system with 64 channels. The system employs Non-Return-to-Zero (NRZ) modulation format at varied bit rates and multiple energy levels. We propose a method for achieving data rates of 10 to 40 Gbps using NRZ modulation and Erbium-Doped Fiber Amplifier (EDFA) over a single-mode fiber transmission distance of 40 to 160 km, along with a dispersion compensation fiber of 8 to 32 km (DCF). The performance of the developed model is evaluated based on Quality Factor, Bit Error Rate (BER), Eye Height, and Threshold. These metrics are measured at two input energy levels from an optical power source, covering a communication capacity ranging from 0.625 Tbps to 2.5 Tbps. Findings: Through the simulations and analyses, we uncover the impact of dispersion and demonstrate the effectiveness of the proposed method in compensating for dispersion effects. Performance analysis of two different input transmitter power levels, -10 dBm is more efficient compared to 0 dBm input transmitter power in terms of bit error rate and quality factor. Novelty: This study presents a novel approach to improving modern communication systems by utilizing DWDM with a dispersion compensation method. The use of a 64-channel DWDM system, combined with the proposed NRZ modulation technique and dispersion compensation fiber, provides an efficient solution for achieving high data rates over long transmission distances while minimizing the effects of dispersion. The findings contribute to the advancement of communication systems for high data rate transmission. Keywords Dispersion effect, Bit Error Rate, Q-factor, Optisystem software, Erbium doped fiber amplifier

Analysis the flat gain/noise figure using RAMAN-Reflective Semiconductor Hybrid Optical Amplifier in C + L + U triple band for super dense wavelength division multiplexing system

Abstract Nonlinearity, flat gain and noise figure are the prime concern for super dense wavelength division multiplexing (SD-WDM) systems which have been resolved from RAMAN-RSOA hybrid optical amplifier (HOA) for the first time in this paper. Channel capacity is taken up to 400 with data rate of 10 Gbps. Performances are evaluated with respect to C + L + U band for 1520–1680 nm and 1520 to 1640 nm. RSOA is operated at 40–120 mA bias current to attain best rating flat gain of 34.07 dB with variation of 3.5 dB than the others HOAs (RAMAN-EDFA, RAMAN-SOA and EDFA-SOA). Moreover, the impact of EDFA-SOA is not acceptable in terms of noise figure for SD-WDM optical communication system.

Implementation and evaluation of two parallel computational models for the simulation of a long‐haul DWDM system limited by FWM

AbstractFour‐Wave Mixing (FWM) is one of the non‐linear phenomena affecting long‐reach communication systems and high bandwidth. Research communities use simulation tools for parameter optimization. Unfortunately, such a simulation is time‐consuming and requires more time as the number of channels increases. This paper proposes two fast implementations of Dense Wavelength Division Multiplexing (DWDM) system, limited by FWM and the intrinsic Amplified Spontaneous Emission (ASE) noise of optical amplifiers employed in each segment. Additionally, this work compares the efficiency and speed improvement of the proposed parallelization model versus an earlier sequential model. We present the computational complexity analysis of sequential and parallel models. The paper considers two different parallel implementations: a multicore processor using Open MultiProcessing (OpenMP) and Compute Unified Device Architecture (CUDA), which is based on the use of a Graphics Processing Unit (GPU). Results show that parallelism using CUDA improves by up to 70 times the simulation performance compared to the sequential model. Parallelism with CUDA is up to 15 times compared to OpenMP using 12 logical processors. It is possible to simulate an increased number of channels within our parallel execution, which was impractical in the sequential simulation.

Optimization Method for Center Frequency Accuracy of High-Channel-Count Arrayed Waveguide Grating in Dense Wavelength Division Multiplexing Systems

The arrayed waveguide grating (AWG) is an essential component in dense wavelength division multiplexing (DWDM) systems. With advancements in optical communication technology, the number of AWG output channels has rapidly increased. However, achieving high center frequency accuracy (CFA) for these channels has become a significant challenge. This paper presents a design and optimization approach for a high-channel-count AWG based on the silica platform and the finite difference beam propagation method (FD-BPM). The causes of center frequency deviation are analyzed, and an optimization method is proposed to adjust the constraint relationship and geometric position of the output waveguides in order to improve CFA. Simulation results demonstrate the excellent optical performance of the designed AWG, achieving a CFA of up to 0.04 times the output channel frequency spacing. The insertion loss, insertion loss uniformity, and adjacent output channel crosstalk are simulated as 1.51 dB, 0.38 dB, and 23.81 dB, respectively. The optimized CFA could compensate for center frequency deviations caused by manufacturing errors and temperature fluctuations. The findings of this research hold potential for extending the optimization to other material platforms and contributing to the development of DWDM systems in the field of optical communication.

Optical fiber systems performance signature based on dispersion compensated methods in dense wavelength division multiplexing systems

Optical fiber systems performance signature based on dispersion compensated methods in dense wavelength division multiplexing systems

Double-Brillouin Frequency Spacing Multi-Wavelength Brillouin Erbium Fiber Laser in Double Cavities Configuration

Multi-wavelength fiber laser has great potential for use in dense wavelength-division multiplexing (DWDM) systems, sensors, and microwave photonics. This paper presents a multi-wavelength Brillouin erbium fiber laser (MW-BEFL) with double-frequency Brillouin spacing of approximately 0.176 nm between each adjacent Stokes. The proposed setup utilizes double cavities configuration for odd and even-order Brillouin Stokes to propagate separately in the system. This configuration is flexible as it can be transformed into a single-spacing MW-BEFL by swapping the ports of the circulator; it can also extract the odd-orders Brillouin Stokes by relocating the OSA in the cavity. Up to 25 double-spaced Brillouin Stokes are obtained with a tuning range of 30 nm. The first 8 Stokes have peak power variation within ± 3.7 dB and an average signal-to-noise ratio of 20 dB.

Design of Ultra Dense WDM Optical Communication System to Reduce Signal Impairments Using DCF and Repeater Techniques

Linear and non-linear impairments are the major problems that affected the dense wavelength division multiplexing (DWDM) system performance. In this simulation designs, two different compensation techniques have been proposed to eliminate signal impairments. The repeater technique was proposed to reduce non-linear effects like four-wave mixing (FWM) which cause transfer power from DWDM channels to another new channels. The dispersion compensation fiber (DCF) technique was used to reduce dispersion effects which cause signal pulse broadening over long transmission distances. Also, three different modulation formats and four frequency separations were used to determine which modulation scheme is more compatible with the compensation techniques. The results is calculated in term of quality factor against power and noetic that the carrier suppressed return to zero (CSRZ) format offers the best performance with the DCF technique with 32.1804 Q-factor at 15dBm threshold power then, the differential phase shift keying (DPSK) format is compatible with the repeater technique with 27.7959 quality factor and 14dBm threshold power. Index Terms— Dense Wavelength Division Multiplexing (DWDM), Dispersion Compensation Fiber DCF, Repeater, and Non-linear Effects.

Electro-optical tunable interleaver in hybrid silicon and lithium niobate thin films.

The interleaver was one of the key devices in dense wavelength division multiplexing (DWDM) applications. In this study, an interleaver with an asymmetrical Mach-Zehnder interferometer structure was designed, fabricated, and characterized in hybrid silicon and lithium niobate thin films (Si-LNOI). The interleaver based on Si-LNOI could be fabricated by mature processing technology of Si photonic, and it was capable of the electro-optical (E-O) tuning function by using the E-O effect of LN. In the range of 1530-1620 nm, the interleaver achieved a channel spacing of 55 GHz and an extinction ratio of 12-28 dB. Due to the large refractive index of Si, the Si loading strip waveguide based on Si-LNOI had a compact optical mode area, which allowed a small electrode gap to improve the E-O modulation efficiency of the interleaver. For an E-O interaction length of 1 mm, the E-O modulation efficiency was 26 pm/V. The interleaver will have potential applications in DWDM systems, optical switches, and filters.

Design and Performance Analysis of Simple WDM Optical Fiber Communication System

WDM (wavelength division multiplexing) is used in this project to simultaneously send data over several channels at high speed. Single mode fiber is favored over Multimode fiber for long-distance communication. As data rate and optical fiber length grow, the quality factor falls. Dispersion effects on an 8-channel dense WDM system at a high data rate will be examined using the Optisystem 10 simulator. A dispersion compensation fiber (DCF) and an Erbium doped fiber amplifier (EDFA) are used to compensate for the dispersion and attenuation in the transmitted optical signal, respectively. Bit error rate (BER) and eye diagram analyzers were used to evaluate the optical communication system's performance.

Investigation of MDRZ and DPSK modulation schemes employed in DWDM systems for smart city 5G access networks

Wavelength division multiplexing (WDM) is one of the emerging technologies for data transmission in 5G access network assembly between the antenna unit (AU) and the distribution unit (DU). Here, in this work, we evaluate and analyze a dense wavelength division multiplexing (DWDM) — passive optical networks (PONs) employing erbium–ytterbium-doped fiber amplifier (EYDFA) [Formula: see text] Raman hybrid optical amplifier (HOA) using two modulation schemes — modified duobinary return to zero (MDRZ) and differential phase shift keying (DPSK) for alternate channels, where the channel count has been varied from 8 to 40. The system has been analyzed over the wavelength span of 1550–1558.8[Formula: see text]nm with a channel spacing, input power and data rate of 25[Formula: see text]GHz, 0[Formula: see text]dB and 40[Formula: see text]Gb/s, respectively. An average gain, gain ripple and optical signal-to-noise ratio (OSNR) of 20.87, 0.95 and 30[Formula: see text]dB, respectively have been observed in the case of HOA along with the achievement of [Formula: see text]-factor of up to 9 at the receiving end of the system. The DPSK-modulated channels result in higher values of gain and OSNR along with lower gain ripple as compared to MDRZ channels making the proposed system a good option for 5G access network applications.

Simulation and design of C + L broadband communication single mode fiber

A novelty CL fiber which can expand L-band communication is proposed to meet the urgent demand of optical fiber transmission bandwidth for large capacity communication system. The influence of L-band attenuation on the OSNR (optical signal-to-noise ratio) of the system is analyzed and calculated; through the simulation of DWDM (dense wavelength division multiplexing) system, the requirements for FAWD (fiber attenuation warping degree) of CL fiber in 100Gbit/s rate DWDM system are obtained; and the influence of waveguide structure design on FAWD is tested. The results show that, the OSNR of L-band for will be 3 dB–3.5 dB worse than traditional C-band on 80 km span system; the FAWD@1625 nm (△α1625) and the FAWDD (fiber attenuation warping degree difference) of CL fiber are recommended to be controlled below 0.015 dB/km and 0.005 dB/km respectively to meet the link requirements in relevant standards. Additionally, it is feasible to improve the attenuation flatness of L-band by optimizing the waveguide structure design which is presented in the paper, that will provide a reference for the large-scale acquisition of novelty CL fibers in the future.

FWM crosstalk reduction and performance investigation of SC-DWDM system employing ML techniques

This article presents a comprehensive approach towards mitigation of four-wave mixing (FWM) induced crosstalk for a super-combined dense wavelength division multiplexing (SC-DWDM) system with in-line erbium-ytterbium doped fiber amplifier (EYDFA) + Raman hybrid optical amplifier (HOA). The performance of modified duo-binary return to zero (MDRZ) and differential phase-shift keying (DPSK) modulation formats employed on alternate channels of the 40-channel system have been compared considering equal (ECSA) and unequal channel spacing allocation (UECSA) schemes at a data rate of 40 Gbps. In the case of the UECSA scheme, the DPSK modulated channels have shown a reduction of FWM crosstalk components and intensities of up to 80% and 40 dB, respectively at a low bit error rate (BER) of 2.5 × 10−14. Different artificial neural network (ANN) techniques have been compared for gain spectrum estimation of HOA has been carried out based on input features of channel spacing, the number of channels and wavelength. Levenberg-Marquardt's (LM) model proves to be the best fit as compared to other ANN techniques. The k-nearest neighbours (KNN), support vector machine (SVM) and decision tree (DT) algorithms have been applied for the estimation of impairments based on root mean square error (RMSE) and coefficient of determination (R2) values as performance metrics. The best-performing model results applying an ANN approach with predicted R2 values of quality - factor (Q-factor) and noise figure (NF) of 0.74 and 0.56, respectively.

5 × 5 Gbps DWDM optical system with DCF and cascaded repeaters techniques.

Dispersion and attenuation problems are the most important factors that limit dense wavelength division multiplexing (DWDM) system performance. Dispersion causes pulse broadening of the optical spectrum, and the attenuation degrades the optical signal. In this paper, dispersion compensation fiber (DCF) and cascaded repeaters techniques have been proposed to reduce linear and nonlinear problems by using two different modulation formats (carrier-suppressed return zero [CSRZ] and optical modulator) and two various channel spacings (100 and 50GHz). The cascaded repeater offers the best performance at 100GHz channel spacing with 37 quality factors for CSRZ and optical modulation schemes; however, the DCF network design is more compatible with the CSRZ modulation format with 27 quality factors. For 50GHz channel spacing, the cascaded repeater offers the best performance with 31 quality factors for CSRZ and optical modulator techniques; the DCF technique comes in next with 27 quality factors for CSRZ and 19 for optical modulators.

Optical Add-Drop Multiplexer for Dense Wavelength Division Multiplexing System Based on Photonic Crystals

Optical Add-Drop Multiplexer for Dense Wavelength Division Multiplexing System Based on Photonic Crystals

Silicon Nanowire-Assisted High Uniform Arrayed Waveguide Grating

Determining how to improve the non-uniformity of arrayed waveguide grating (AWG) is of great significance for dense wavelength division multiplexing (DWDM) systems. In this work, a silicon nanowire-assisted AWG structure is proposed, which can achieve high uniformity with a low insertion loss. The article compares the effect of nanowire number and shape on uniformity and insertion loss, finding that double nanowires provide the best performance. Double nanowires with a width of 230 nm and length of 3.5 μm can consist of a slot configuration between arrayed waveguides, both connecting to the star coupler and spacing 165 nm from the waveguides. Compared with conventional 8- and 16-channel AWGs with channel spacing of 200 GHz, the non-uniformity of the presented structure can be improved from 1.09 and 1.6 dB to 0.24 and 0.63 dB, respectively. The overall footprint of the device would remain identical, which is 276 × 299 or 258 × 303 μm2 for the 8- or 16-channel AWG. The present high uniformity design is simple and easy to fabricate without any additional insertion loss, which is expected to be widely applied in the highly integrated DWDM systems.

Design and Analysis of Ultralow Voltage Graphene on the Silicon Rich Nitride Tunable Ring Resonator-Based Add-Drop Filter for DWDM Systems

We propose and simulate a third-order 3D electro-optically highly tunable compact add-drop filter based on nonlinear microring resonators. The used tuning mechanism relies on enhanced Kerr nonlinearity in a graphene layer integrated on top of a two-photonabsorption-free and low loss silicon-rich nitride core material at telecommunication wavelengths. An ultrahigh tuning efficiency (150 pm/V) over a tuning range of 1.3 nm, ensuring ultralow voltage consumption, was achieved in this work. We used titanium oxide and silicon oxide as the upper-cladding and under-cladding materials, respectively, around the silicon-rich nitride core material, to come up with a polarization-insensitive, and the thermally resilient third-orderadd-drop optical filter in the L band (1565 nm–1625 nm) with a full wave at a half maximum bandwidth of 50 GHz (linewidth of 0.4 nm) around 1570 nm, a high-free spectral range of 18.5 nm, a quality factor of 2580, an extinction ratio of 60 dB, a finesse of 19, and a thermal stability of 0.3 pm/K. A three-dimensional multiphysics approach was used to simulate the propagation of transverse electric and transverse magnetic polarized waves through the filter, combining the electromagnetic features with thermo-optic and stress-optical effects. The contribution of this work to the existing literature is that the designed filter proposes a new and highly tunable material system compatible with the complementary metal-oxide-semiconductor fabrication technology while combining high tunability, polarization insensitivity, and high thermal stability features for an ultracompact and energy-efficienton-chip integrated photonic tunable filter for dense wavelength division multiplexing systems in the less occupied L band.

Enhancement of traveling wave semiconductor optical amplifier approach for DWDM communication system

In this study, the high performance of dense wavelength division multiplexing (DWDM) by using a traveling wave semiconductor optical amplifier (TW-SOA) at a channel spacing of 100 GHz is investigated, in terms of (Q-factor, injected current, transmitted power, gain). The Optisystem software is employed to send the different range of input power over the different ranges of the TW-SOA injected current with optimized TW-SOA parameters. The data rate of trans- mission optical signal up to 300 Gb/s at -35 dB input signal power have been investigated. The better results have been measured of the information signal with high quality and gain, when the range of input power is corresponding to the optimized range of injected current for the signal to be transmitted effec- tively. The present communication also supports various numbers of users with the same data rate of 5 Gb/s which is used to check the high quality of the signal in the receiver.

DFB laser array based on four phase-shifted sampled Bragg gratings with precise wavelength control.

A four-laser array based on sampled Bragg grating distributed feedback (DFB) lasers in which each sampled period contains four phase-shift sections is proposed, fabricated, and experimentally demonstrated. The wavelength spacing between adjacent lasers is accurately controlled to 0.8 nm ± 0.026 nm and the lasers have single mode suppression ratios larger than 50 dB. Using an integrated semiconductor optical amplifier, the output power can reach 33 mW and the optical linewidth of the DFB lasers can be as narrow as 64 kHz. This laser array uses a ridge waveguide with sidewall gratings and needs only one metalorganic vapor-phase epitaxy (MOVPE) step and one III-V material etching process, simplifying the whole device fabrication process, and meeting the requirements of dense wavelength division multiplexing systems.

Magnetically Tunable Micro-Ring Resonators for Massive Magneto-Optical Modulation in Dense Wavelength Division Multiplexing Systems.

We demonstrate, numerically, a new concept for on-chip magneto-optical (MO) modulation in dense wavelength division multiplexing (DWDM) applications. Our idea uses materials and mechanisms that are compatible with current silicon-on-insulator fabrication and CMOS technologies for monolithic integration. The physics behind our idea stems in the exploitation of the enhanced MO activity of a micro-ring, made of cerium substituted yttrium iron garnet (Ce:YIG) material, to actively manipulate the resonance wavelengths of an adjacent micro-ring resonator (MRR) of silicon (Si). This active manipulation of the latter MO-MRR structure is used to modulate the optical signal traveling through a side-coupled Si bus waveguide. Moreover, by proper tailoring multiple MO-MRRs (side-coupled to the single Si bus waveguide) to match wavelength channels in DWDM across the entire C-band optical communications spectrum, we extend our proposal to massive and dynamic MO modulation in DWDM applications. Significantly, we noticed that the active MO shifting of the resonant wavelength (used for MO modulation here) can be used for improvements in the spectrum utilization efficiency in future elastic optical networks (EONs).

Tunable Semiconductor Laser Based on Surface High-Order Bragg Gratings With 62 × 50 GHz Wavelength Tuning

A tunable semiconductor laser based on surface high-order Bragg gratings with 50 GHz channel spacing is demonstrated for the first time. The tunable semiconductor laser can cover 62 channels at 25 °C, and the side mode suppression ratio (SMSR) of each channel is larger than 34 dB. To achieve such properties, the number, depth and periods of the slots of the tunable semiconductor laser are optimized by the 2-D scattering matrix method (SMM) to obtain denser reflection peaks with smaller full width at half maximum (FWHM) and higher reflectivity. The tunable semiconductor laser can be widely used in dense wavelength division multiplexing (DWDM) systems and can provide a promising light source for photonic integrated circuits.