Dense Wavelength Division Multiplexing Research Articles

Penalty mitigation for OSC-induced XPM in long-haul WDM coherent systems by digital up-conversion coding.

Due to the cross phase modulation (XPM) effect, in long-haul high-speed dense wavelength division multiplexing (DWDM) coherent systems, using a low-speed on-off-keying (OOK) format optical supervisory channel (OSC) will introduce extra nonlinear phase noise, which restricts the transmission distance. In this paper, we propose a simple OSC coding method to mitigate the OSC-induced nonlinear phase noise. According to the split-step solution of the Manakov equation, we up-convert the baseband of the OSC signal out of the pass-band of the walk-off term to reduce the spectrum density of XPM phase noise. Experimental results show that the optical signal to noise ratio (OSNR) budget on the 400 G channel of 1280-km transmission is improved by 0.96 dB, which achieves almost the same performance with the no OSC case.

800G/$\lambda $ Self-Homodyne Coherent Links With Simplified DSP for Next-Generation Intra-Data Centers

Assuming a low-latency forward error correction (FEC)-based bit-error-rate (BER) threshold, we demonstrate and provide a detailed analysis of a 120 Gbaud/DP-16QAM single-carrier self-homodyne coherent link in the C-band. Through theoretical and simulation analysis as well as experimental investigation, we find that a minimum receiver DSP based on a simple I-Q correction scheme is needed to compensate for the combined effect of fiber dispersion, I-Q phase rotation, transmitter I-Q impairment, and receiver skew in combination with a finite analog to digital converter (ADC) resolution. Based on the simplified DSP, we demonstrate link budgets of 4.5 dB (for 16 amplified dense wavelength division multiplexing (DWDM) channels) and 5.2 dB (unamplified single-channel case). The amplified DWDM self-homodyne coherent system provides a 12.8 Tb/s capacity per fiber pair and is useful for bandwidth-demanding intra-data center applications.

An integrated device for electro-optic modulation and dense wavelength division multiplexing based on photonic crystals

We proposed an integrated device for electro-optic (EO) modulation and dense wavelength division multiplexing (DWDM) based on photonic crystals (PhCs). The transmittance performance of the designed structure was modelled and analyzed according to the time-domain coupled mode theory (CMT), using three-dimensional finite-difference time-domain (3D-FDTD) method to calculate the parameters of the proposed device for verification. The numerical results show that the proposed integrated device can realize the functions of “on”, “off” modulation and DWDM with a channel spacing of 0.8 nm at the operating wavelengths of 1555 nm and 1554.2 nm. The minimum insertion loss, channel crosstalk and modulation voltage are 0.7 dB, − 29.04 dB and 0.88 V, respectively. The maximum extinction ratio and modulation speed are 21.51 dB and 29.4 GHz. The designed integrated device has the advantages of low loss, compact size (41.28μm×11.18μm), narrow channel spacing, large extinction ratio, which can be easily expanded the number of channels and used in highly integrated large-capacity optical communication systems and data center.

KM3NeT broadcast optical data transport system

The optical data transport system of the KM3NeT neutrino telescope at the bottom of the Mediterranean Sea will provide more than 6000 optical modules in the detector arrays with a point-to-point optical connection to the control stations onshore. The ARCA and ORCA detectors of KM3NeT are being installed at a depth of about 3500 m and 2500 m, respectively and their distance to the control stations is about 100 kilometers and 40 kilometers. In particular, the two detectors are optimised for the detection of cosmic neutrinos with energies above about 1 TeV (ARCA) and for the detection of atmospheric neutrinos with energies in the range 1 GeV–1 TeV (ORCA). The expected maximum data rate is 200 Mbps per optical module. The implemented optical data transport system matches the layouts of the networks of electro-optical cables and junction boxes in the deep sea. For efficient use of the fibres in the system the technology of Dense Wavelength Division Multiplexing is applied. The performance of the optical system in terms of measured bit error rates, optical budget are presented. The next steps in the implementation of the system are also discussed.

Design of DWDM optical communication systems with different modulation formats using DCF and a repeater.

The dense wavelength division multiplexing (DWDM) technique has been used to provide a large capacity and low bandwidth loss for optical communication systems. In this paper, simulation designs by Optisystem15.0 of carrier-suppressed return to zero (CSRZ), differential phase shift keying (DPSK), and intensity modulation is proposed to determine which modulation format is more compatible with four and eight DWDM channels for transmitting an optical signal over 400km distance. For a long optical path, the dispersion compensation fiber (DCF) technique is proposed to eliminate dispersion effects and increase the possibility of transmitting multiple optical wavelengths over long single-mode fiber. Optical amplifiers are used to amplify the optical signal with a distorted signal and process the attenuation caused by the long transmission distance. In DCF network design, CSRZ offers the best performance because of the large quality factor (24.560) and high threshold power (15dBm), which make the system compatible with increased distance between the transmitter and receiver; next is intensity modulation with a 24.5604 quality factor and 13dBm threshold power value; DPSK comes in last with the worst performance, with a quality factor of 10 at 13dBm power due to non-linear effects, especially non-linear phase noise. In the repeater design, the DPSK modulation format has the best performance with a large quality factor of 20.7913 at a high threshold power of 14dBm for 150GHz spacing; this is because the repeater technique is compatible with reducing the non-linear effects of the DPSK format. CSRZ and intensity modulation have the same performance with a 12 quality factor at 4dBm power for intensity modulation and 3dBm power for CSRZ modulation.

Intensification and Interpretation of Performance in 5G adopting Millimeter Wave: A Survey & Future Research Direction

In context of high speed broadband communication, 5G optical communication has become a most stimulating and motivating domain in research. Recent cellular network LTE (4G) will not be adequate and effective to fulfill the needs of higher data rate, higher bandwidth, low latency and Quality of service.To achieve the above requirements and to address the challenges 5G optical communication have major considerations, the incorporation of Dense Wavelength Division Multiplexing (DWDM), Millimeter wave (mm-wave) communication, eMBB to make efficient decisions.This article summarize the empowering technology for DWDM, mm-wave signal communication and enhanced Mobile Broadband uses 5G optical communication as an evolution from 4G-LTE communication amenities, with fast communications, good throughput and high capacity, it is a successful aspirant for the increasing broadband communications. Such empowering technology, focused mainly on improving the network structure and efficiency, involves producing the mm-wave broadband signal with easy and cost adequate systems. This paper gives a thorough review on developing and empowering advancements identified with optical communication framework that can meet the huge data rate request of broadband. The article further addresses the research gaps and outlines the important future research direction for enhancing communication using DWDM.

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

Improve Quality Factor by Using DWDM Technology for Long Distances and Different Power Levels

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 Q-factor 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.

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.

Theoretical analysis of quantum key distribution systems when integrated with a DWDM optical transport network

Theoretical research and numerical simulation of the noise influence caused by spontaneous Raman scattering, four-wave mixing, and linear channel cross talk on the performances of quantum key distribution (QKD) systems were conducted. Three types of QKD systems were considered: a coherent one-way QKD protocol, subcarrier-wave QKD system, and continuous-variable QKD integrated with classical dense wavelength division multiplexing (DWDM) channels. We calculate the secure key generation rate for the systems mentioned addressing different channel allocation schemes (i.e., configurations). A uniform DWDM grid is considered with a quantum channel located in the C-band and O-band (at 1310 nm) of a telecommunication window. The systems’ performances are analyzed in terms of the maximal achievable distance values. Configurations for further analysis and investigation are chosen optimally, i.e., their maximal achievable distances are the best.

Capacity enhancement in fiber optic communication systems using space division multiplexing

Abstract Data rates in fiber optic communication (FOC) technology are highly increased and optical communication technology has been mostly advancing highly. There are different multiplexing techniques like frequency-division multiplexing (FDM), time-division multiplexing (TDM), wavelength division multiplexing (WDM), dense wavelength division multiplexing (DWDM), code division multiplexing (CDM), and digital coherent technology by using single mode fiber (SMF)/single core fiber (SCF), and using these multiplexing did not produce over 100 Tbps/fiber because of many factors like linearity and nonlinearities of fiber optic. To transmit a high capacity over 100 Tbps/fiber and long-haul transmission, the multiplexing techniques that are needed to break this bottleneck/capacity limit are termed space-division multiplexing, which uses single mode fiber (SMF) and multicore fiber (MCF). The target of this paper is to enhance the capacity of FOC systems using space-division multiplexing (SDM). The result produced during this paperwork is that the capacity enhanced is around 14.75 pb/s/fiber, after it is decreasing and thus the haul of transmission is 250 km with usable wavelength C + L band. The signal/noise ratio is 35 dB in FOC using single mode fiber (SMF) and multicore fiber (MCF). Finally, the SDM includes a great role in fiber optic just in case of effective information transmission by enhancing capacity, reduction of loss, distortion, cross talk, and power consumption reduction during information transmission; SDM in fiber optic is incredibly essential for effective communication systems with extremely high capacity and long haul transmission.

Analysis of an injection-locking-loophole attack from an external source for quantum key distribution

Many security loopholes exist in quantum key distribution (QKD) due to the imperfections of realistic devices. On the source side, the decoy-state method can defend against the most severe photon-number-splitting (PNS) attack and improve the performance of QKD. Measurement-device-independent QKD and twin-field QKD have further closed all loopholes on the detection side. In this paper, we propose a valuable optical injection-locking loophole for the case when the internal isolator inside the laser is removed. We first introduce the effects of the injection locking with different injection intensities on the source frequency. Through the successive responses of adjacent pulses from frequency ports of the dense wavelength division multiplexer, the decoy state and the signal state can be partially distinguished. The specific injection-locking-loophole analysis of the isolatorless decoy phase-encoding Bennet-Brassard 1984 QKD and decoy phase-matching QKD protocols with external optical injection has been deeply studied. Simulation results show that, if we maintain the same observed gain statistics as normal after an external optical injection locking, the loophole cannot be exploited for a PNS attack when the QKD distance is short. As the QKD distance increases, a PNS attack at a medium distance using the optical injection-locking loophole does not threaten the security; the security is still valid. With the further increase of the QKD distance, the lower-bound secure key rate is higher than the upper-bound secure key rate given by a PNS attack at a long distance, some of the keys must be insecure, and information will be leaked.

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.

An Energy-Efficient and Bandwidth-Scalable DWDM Heterogeneous Silicon Photonics Integration Platform

Heterogeneous III-V-on-silicon photonic integration has proved to be an attractive and volume manufacturable solution that marries the merits of III-V compounds and silicon technology for various photonic integrated circuit (PIC) applications. The current main-stream Ethernet trends for larger bandwidth are pushing higher modulation baudrate or employing advanced modulation format for datacom applications. However, neither solution is likely able to significantly drive overall solution cost and energy efficiency to the best sweet spot, nor to unfold the full potential of heterogeneous integration. Here we review our innovations on a special heterogeneous III-V-on-silicon platform, and the development of a dense wavelength division multiplexed (DWDM) transceiver. A 40-channel DWDM architecture and platform fabrication are discussed first, followed by experimental demonstration of each high-quality building block. InAs/GaAs quantum dot material is the choice for building robust multi-wavelength lasers, amplifiers, and high-speed avalanche photodetectors (APDs) which complements the more mature SiGe APDs. A metal-oxide-semiconductor capacitor phase shifter is a mission critical structure to provide athermal and efficient tuning for deinterleavers and microring resonators, and high-speed modulation. A successful 8 × 25 Gb/s link demonstration paves the way for the world's first fully-integrated DWDM PIC on Si with Terabit/s aggregated bandwidth and energy efficiency likely to ∼100 fJ/bit.

Analysis of an active and passive optical fronthaul with dense wavelength division multiplexing for coexisting 4G/5G cloud radio access network architectures based on software defined radio

We experimentally investigate the performance of an active and passive optical fronthaul to be employed in a cloud/centralized radio access network (C-RAN) architecture based on software-defined radio (SDR) for 4G systems, and we discuss the viability to integrate these fronthaul configurations in coexisting 4G/5G systems based on SDR by considering the reconfigurable characteristics of SDRs and the capacity and latency characteristics of the optical fronthaul. The active optical fronthaul consists of two transponders employing dense wavelength division multiplexing (DWDM), whereas the passive optical fronthaul consists of a point-to-point scheme based on DWDM only. To perform a comparative study between the active and passive optical fronthaul in the C-RAN architecture, we have measured the throughput (bit rate) generated via iPerf® for uplink and downlink transmissions at different DWDM channels, and we analyze the losses and latency presented in both optical fronthaul schemes. We found that for different optical fronthaul lengths up to 21.76 km, the bit rate is practically the same for the passive and active fronthaul despite the higher optical losses present in the passive fronthaul in comparison to the active fronthaul. In addition, the latency among active and passive fronthaul are almost similar with an estimated increment of 20 μs in the active fronthaul. These results are independently of the number of remote radio heads (RRHs) and user equipment (UEs) considered in the C-RAN architecture. Our findings put forward the proposed DWDM passive fronthaul as a viable, less complex, and cost-sensitive solution for C-RAN systems with fronthaul lengths up to 21.76 km. These results and all the experiences reported on the C-RAN implementation provide valuable information to design and develop 4G and 5G C-RAN architectures based on SDR with the capability to operate in a DWDM optical fronthaul infrastructure.

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).

Modernization of Dense Wavelength Division Multiplexing (DWDM) Route Surabaya-Bangil To Increase Optical Network Capacity

Along with the increasing demand for data networks, on the Java island network traffic, especially the Surabaya - Bangil link, the operator increases the channel capacity by modernizing DWDM (Dense Wavelength Division Multiplexing) technology in its transmission equipment. At that time, the DWDM technology was DWDM 6800 with a maximum capacity of one port that could only accommodate 10 Gbit/s, while using DWDM 9800, the maximum capacity of one port could accommodate up to 100 Gbit/s. Modernization of DWDM 6800 to DWDM 9800 technology uses the cross-connect method so that it does not require many costs and can be done within a short duration of time so that network performance can be adequately maintained. As a result, after modernization, the network has sufficient reserves to cover demand for the next few years.

Mitigating the Effect of Chromatic Dispersion in Shared Path Optical Network using Intelligent Dense Wavelength Division Multiplexing Techniques

Mitigating the Effect of Chromatic Dispersion in Shared Path Optical Network using Intelligent Dense Wavelength Division Multiplexing Techniques

Design and analysis of a channel drop filter and demultiplexer based on a photonic crystal super ellipse-shaped ring resonator

In advanced optical communication systems, a photonic crystal (PC) based channel drop filter (CDF) and dense wavelength division multiplexer (DWDM) demultiplexer are essential components in the design of a complete DWDM system, which offers a high transmission data rate. In the present work, a novel PC, CDF filter and demultiplexer based on a ring resonator with a super ellipse shape is designed and analyzed. To design a high-performance device, the performance parameters of the proposed components, such as transmission efficiency, spectral line width, channel spacing, Q-factor and crosstalk, are investigated. The proposed CDF is designed to drop a resonant wavelength with a high quality factor of 3955, and the ring resonator design is extended to the demultiplexer. The demultiplexer is designed to drop the four resonant wavelengths of 1579.8 nm, 1582 nm, 1583.6 nm and 1574.9 nm, respectively. The observed high quality factor (3955), bandwidth (0.4 nm) and transmission efficiency (90%) of the proposed demultiplexer will support high-performance DWDM systems

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.