Hybrid Wavelength Division Research Articles

Hybrid WDM/MDM (De) multiplexer based on Fabry–Perot resonators with Bragg grating reflectors

The traveling-wave-like Fabry–Perot (TW-like F-P) resonators, utilizing transverse-mode conversion, have been thoroughly investigated as on-chip filters. However, the asymmetric directional coupling (ADC) between the phase shifter and the output waveguide in this structure is not fully utilized, resulting in a rare implementation of hybrid wavelength division multiplexing (WDM) and mode division multiplexing (MDM). In this paper, using the transfer matrix method (TMM), we investigate methods to effectively enhance the quality factor (Q-factor) of TW-like F-P resonators. This is achieved by increasing the phase shifter length and reducing the coupling coefficient between these waveguides, without significantly impacting the channel drop efficiency. MDM can be achieved by adjusting the width of the output waveguides, utilizing the ADC between the phase shifter and the output waveguide. We design nine-channel hybrid WDM-MDM multiplexers based on TW-like F-P resonators. The variational-finite-difference time-domain (varFDTD) method is utilized to analyze the device’s performance, and its single channel extinction ratio (ER) values can reach −20dB. This work paves the way for TW-like F-P-resonator-based large capacity optical communications and interconnections.

On-Chip Optical Switching Network Architecture Based on Hybrid Wavelength and Mode Division Multiplexing

On-Chip Optical Switching Network Architecture Based on Hybrid Wavelength and Mode Division Multiplexing

Hybrid WDM-FSO-PON with integrated SMF/FSO link for transportation of Rayleigh backscattering noise mitigated wired/wireless information in long-reach

This paper presents a hybrid Wavelength division multiplexing-free space optics-passive optical network for bidirectional transmission with 4×10 Gbps downlink and 2×10 Gbps uplink to provide information to the wired and wireless users simultaneously over total 60 km SMF and 650 m FSO or 62 km SMF link with enhanced fault protection capability. Noise tolerance against Rayleigh backscattering (RB) also enhanced by employing two different ports of interleavers and by allowing different wavelengths of light as carrier signals for uplink and downlink transmission through a single feeder fiber. Integrated single mode fiber (SMF)/free space optics (FSO) link increase the reliability against failure of any one channel between SMF and FSO link, besides that it maintains the continuity of data transfer even where fiber link installation is restricted due to environmental boundary such as between two mountains, wide river etc. Low bit error rate (10−9), <1 dB power penalties (0.7 dB, 0.85 dB, 0.9 dB) are obtained between B2B and over total transmission link. A comparison between our proposed network and the network when the signal transmitted over total transmission link (60 km SMF+ 650 m FSO, or 62 km SMF) at a time also verified with their power budgets. Divergence losses at different FSO lengths (17 m to 680 m) are also calculated to determine the maximum possible FSO length for this proposed set up. Therefore, the proposed architecture proofs its feasibility, reliability and the capacity to continue transfer of high data rate over long distance even in the unfair environmental situation, which makes it an attractive platform to the next generation communication system (5G) to fulfill the thirst of end users.

A Cost-Efficient RGB Laser-Based Visible Light Communication System by Incorporating Hybrid Wavelength and Polarization Division Multiplexing Schemes

Visible light communication (VLC) has been proven a promising technology to counter the limitations of radio frequency (RF) communication technology such as high interference and high latency issues. VLC offers high bandwidth as well as immunity to interference from other electromagnetic spectrums. Due to these features, VLC can be an excellent solution for biomedical and healthcare applications for transmission of body sensor signals and other crucial patient information. In this work, a highly efficient VLC system is designed to transmit six channels, with each one carrying 10 Gbps of data, over a 500 m optical fiber link and a 200 cm VLC link. To make the VLC system cost effective, simple and efficient on-off keying (OOK) (non-return to zero) is used as the encoding scheme. Moreover, to further enhance the capacity and bandwidth of the proposed VLC system, hybrid wavelength division multiplexing (WDM) and polarization division multiplexing (PDM) schemes are incorporated by using red, green, and blue lasers. The reported results show the successful transmission of all channels (6 × 10 Gbps) over 500 m optical fiber and 200 cm of VLC link.

Performance analysis of high speed backward compatible TWDM-PON with hybrid WDM–OCDMA PON using different OCDMA codes

In this paper, a backward compatible bidirectional 160/40 Gbps time and wavelength division multiplexing-passive optical network with hybrid wavelength division multiplexing optical code division multiple access PON (WDM–OCDMA PON) has been proposed. Six OCDMA codes have been used to enhance the security and users’ ability to access shared bandwidth of an optical network. In this “pay-as-you-grow” supported system, the fiber impairment effects have been effectively reduced. The performance of the proposed system has been analyzed for variable input power (4–19 dBm) and transmission distance (10–70 km) supporting 120 active users under the influence of fiber nonlinearities, attenuation, dispersion and noise. Based on the numerical calculations, the proposed system using modified quadratic congruence (MQC) code is shown to provide better performance compared to multi diagonal, hadamard, zero cross-correlation (ZCC), shift ZCC and flexible cross-correlation codes. To validate the numerical analysis, the simulation of the proposed system at 160/40 Gbps data rate for 70 km downstream and greater than 70 km upstream fiber link transmission at 10−9 BER limit for 68 active users have been successfully demonstrated. Also, it has been shown that MQC code provides optimum results at 10 dBm input power over 55 km distance and supports more than 120 active users with high gain of − 1.97 dB and low noise figure of 2 dB. Further, the comparative performance of the proposed system with the previous latest works in literature reveals a superior performance of the system.

Potential Threats and Possible Countermeasures for Photonic Network-on-Chip

Design flaws and unseen vulnerabilities in the photonic network-on-chip (PNoC) have made it a focal point of potential security attacks. Previous works well investigate remote attacks launched outside from electrical NoCs. However, it is still a challenge to find possible threats and efficient countermeasures for PNoCs. In PNoCs, for example, micro resonators can be maliciously controlled by a remote attacker to miss expected tuning function, thus leading to data loss and information disclosure. In this article, we first summarize remote denial of service attacks caused by hardware Trojan insertion and timing channel in NoCs. We then show that these two kinds of remote attacks are also effective threat models in PNoCs. We design, for the first time, countermeasures protecting against threat models in the hybrid wavelength and mode division multiplexing PNoC. Finally, we propose the challenging issues of enhancing the safety of the 3D PNoC under new potential threats.

A high-speed radio-over-free-space optics link using wavelength division multiplexing-mode division multiplexing-multibeam technique

Radio-over-Free-Space Optics (RoFSO) is a key technology for providing high-speed communication links in rural areas. In this work, an orthogonal frequency division multiplexing based RoFSO transmission link has been designed by adopting hybrid wavelength division multiplexing (WDM), mode division multiplexing (MDM) and multibeam technique. The proposed link is investigated under heavy fog weather conditions and its performance is compared for 1-beam and 4-beams transmission using numerical simulations. The numerical results show faithful transportation of high-speed data at 2000 m with acceptable performance of the link. Furthermore, the link performance is compared with previously reported works and the proposed RoFSO link with hybrid WDM-MDM-multibeam technique demonstrates an enhanced link range and transmission capacity performance.

Design of a hybrid transmission system using wavelength division multiplexing and subcarrier under the frequency frame for 5G

This article proposes the design of a hybrid transmission system using wavelength division multiplexing and subcarrier under the frequency frame for 5G. The proposal is evaluated through modeling based on simulation of the generation of optical carriers using a broadband source in combination with an optical filter configured with different pass bands and transmission at different distances. The simulation model evaluated the signal quality levels in terms of the Q factor, taking into account the frequency framework for 5G (5 GHz, 30 GHz and 60 GHz) and the optical fiber length (5 km, 10 km, 15 km, 20 km, 25 km, 30 km). The results obtained show that the best performance of the Q factor compared to distances was that of the 30 GHz frequency, both in the access network and in the metro network. It was also possible to demonstrate that through a broadband light source and a waveguide grating array it is possible to obtain optical carriers for the transmission of signals in a hybrid wavelength division multiplexing and subcarrier transmission system.

Design of 3.84 Tbps hybrid WDM–PDM based inter-satellite optical wireless communication (IsOWC) system using spectral efficient orthogonal modulation scheme

Inter satellite optical wireless communication (IsOWC) is an emerging transmission technology which is capable of transporting high-speed data between two satellites estranged in outer space and revolving in the same or different orbits. IsOWC links have been considered very crucial for the purpose of providing global coverage for information transmission throughout the world. This work reports the modeling and performance investigation of a novel hybrid wavelength division multiplexing–polarization division multiplexing based IsOWC transmission system incorporating an orthogonal modulation scheme combining carrier suppressed return to zero–differential quadrature phase shift keying–polarization shift keying formats to transmit three independent 40 Gbps data streams simultaneously at different signal parameters. The results show a successful transmission of 3.84 Tbps information over 58,000 km link range with acceptable Q Factor (> 6 dB) and BER (≤ 10−9) using the proposed system. The performance comparison of the proposed system with existing work has also been discussed in this paper.

Multi-Micron Silicon Photonics Platform for Highly Manufacturable and Versatile Photonic Integrated Circuits

We describe and characterize a multi-micron silicon photonics platform that was designed to combine performance, power efficiency, manufacturability, and versatility for integrated photonic applications ranging from data communications to sensors. We outline the attributes needed for broad applicability, high-volume manufacturing, and large-scale deployment of silicon photonics, and describe how the platform is favorable with respect to these attributes. We present demonstrations of key technologies needed for the communications and sensing applications, including low-loss fiber attach, compact low-loss filters, efficient hybrid wavelength division multiplexed lasers, and high-speed electro-absorption modulators and integrated photodetectors.

Microstructured Optical Fiber Based Distributed Sensor for In Vivo Pressure Detection

Microstructured optical fiber based distributed pressure sensor is proposed and demonstrated for high resolution manometry (HRM), which adopts the hybrid wavelength and frequency division multiplexing architecture, and hyperelastic packaging. The microstructure acting as a sensing element is composed of two identical and closely spaced ultrashort fiber Bragg gratings with the reflectivity of only 1%. In theory, 243 microstructures can be multiplexed along one single fiber with an interval of 10 mm beneficial from the compact structure, hybrid encoding feature, and low insertion loss. Homogeneous elastic packaging is explored to protect the fiber and greatly enhance the lateral pressure sensitivity of the sensor. Moreover, a mechanical model is established through the finite element method to analyze the sensitizing effect of the packaging. A prototype system is built and experimentally demonstrated the distributed pressure measurement with the spatial resolution of 10 mm and the pressure sensitivity up to 2.2 Nm/mPa. Due to the advantage of high spatial resolution, high multiplexing capacity, and high pressure sensitivity, the proposed sensor is suitable for HRM in medical application.

Investigation on Pointing Error in Multi-Beam Free Space Optical Communication System

Abstract Free space optical (FSO) communication has fascinated a lot of attention for a variety of applications in telecommunication area. It is dream of every researcher and telecommunication society to make it a real alternative solution for the last mile problem, to replace fiber optics. FSO is much favored because of its low maintenance cost and deployment time. Pointing error is one of the main challenges in FSO communication system which affects its performance especially at high data links that leads to significant performance degradation. In this paper, the impact of pointing error for multi-beam Hybrid Wavelength Division Multiplexing (HWDM) FSO system is investigated. Then the effect of link distance and Bit Error Rate (BER) are estimated by accounting the pointing error and atmospheric attenuation. The effect of change of link distance is examined while changing the number of beams between the transmitter and receiver as well. In this attempt, the HWDM system is considered by combining eight Dense Wavelength Division Multiplexing (DWDM) channels and four Coarse Wavelength Division Multiplexing (CWDM) channels. In addition, the influences of BER and receiver sensitivity are analyzed for the proposed system by incorporating Erbium Doped Fiber Amplifier (EDFA) at the receiver end. The data rate 2.5 Gbps is considered for both CWDM and DWDM channels for investigation.

High-Speed and High-Resolution Demodulation System for the Hybrid WDM/FDM Based Fiber Microstructure Sensing Network

A hybrid wavelength-division multiplexing/frequency-division multiplexing (WDM/FDM) based optical fiber microstructure sensing network with large capacity, high resolution, and high-speed response is proposed and demonstrated. The sensing network is composed of a demodulation system and a fiber microstructure sensor array distributed along a single fiber. Parallel processing technology is utilized for investigating the envelope peak and the fringe peak of the spectrum simultaneously, which can be used to distinguish large-scale temperature shifts quickly. In combination with a high-speed tunable Fabry-Perot filter, the sensor array can be quickly demodulated with the speed up to 500 Hz as well as the wavelength resolution less than 3 pm. In a proof-of-concept experiment, an array composed of 16 sensors through four WDM and four FDM is employed for temperature measurement, demonstrating a temperature resolution less than ±0.3 °C, and a vibration experiment verified 500 Hz demodulation speed capacity. Compared with traditional demodulation schemes, the proposed demodulation system is suitable for large capacity networks and dynamic sensing applications.

Performance Investigation of 1.68 Tb/s Spectral Efficient Hybrid OTDM–WDM System Using Orthogonal Modulation Format

In this paper, the performance of return-to-zero/differential quadrature phase shift keying/polarization shift keying (RZ/DQPSK/PolSK) orthogonal modulation format is investigated in hybrid optical time division and wavelength division multiplexing (OTDM–WDM) technique to increase the spectral efficiency of the system. The error free performance is achieved over 140 km transmission with the acceptable bit error rate (~ 10−12). The original contribution of this paper is to propose a bandwidth efficient OTDM–WDM system that could be projected even in high speed scenario and expected to be more technical viable due to use of optical orthogonal modulation formats.

High capacity hybrid WDM/TDM-PON employing fiber-to-the-home for triple-play services with 128 ONUs

A hybrid wavelength division multiplexing/time division multiplexing passive optical network (WDM/TDM) PON employing fiber-to-the-home (FTTH) for triple play services with 128 optical network units has been proposed and demonstrated, to transmit data, voice and video services simultaneously. 10 Gbps differential phase shift keying signal is employed to symbolize the internet and voice component. The radio frequency (RF) and sub carrier multiplexing scheme are utilized to comprehend analog video services. The multiplexed RF and data signal is modulated by external LiNbO3 phase modulator to mitigate chromatic dispersion and to obtain a small power penalty in receiver. The results show that FTTH triple play services can be successfully transmitted over a distance of 50 km with low transmission power penalties and better receiver sensitivity. High Q-factor, low bit-error-rate and excellent eye-diagram are achieved in our proposed network system and the results affirm the acceptability of proposed high capacity radio over fiber based hybrid WDM/TDM-PON.

Energy efficient flexible hybrid wavelength division multiplexing-time division multiplexing passive optical network with pay as you grow deployment

A flexible hybrid wavelength division multiplexing-time division multiplexing passive optical network architecture that allows dual rate signals to be sent at 1 and 10 Gbps to each optical networking unit depending upon the traffic load is proposed. The proposed design allows dynamic wavelength allocation with pay-as-you-grow deployment capability. This architecture is capable of providing up to 40 Gbps of equal data rates to all optical distribution networks (ODNs) and up to 70 Gbps of a asymmetrical data rate to the specific ODN. The proposed design handles broadcasting capability with simultaneous point-to-point transmission, which further reduces energy consumption. In this architecture, each module sends a wavelength to each ODN, thus making the architecture fully flexible; this flexibility allows network providers to use only required OLT components and switch off others. The design is also reliable to any module or TRx failure and provides services without any service disruption. Dynamic wavelength allocation and pay-as-you-grow deployment support network extensibility and bandwidth scalability to handle future generation access networks.

WDM/OCDM Energy-Efficient Networks Based on Heuristic Ant Colony Optimization

The ant colony optimization for continuous domains $(\text{ACO}_{\mathbb{R}})$ approach is deployed in order to solve two resource allocation (RA) optimization problems associated to the signal-to-noise plus interference ratio metric with quality-of-service constraints in the context of hybrid wavelength-division multiplexing/optical code-division multiplexing networks. The $\text{ACO}_{\mathbb{R}}$ - based RA optimization strategy allows optimally regulating the transmitted optical powers, as well as maximizing the overall energy efficiency (sum EE) of the optical network. In this context, a suitable model for heuristic optimization approach is developed, with emphasis on the network performance under optimized $\text{ACO}_{\mathbb{R}}$ input parameters. Extensive simulation results for both power allocation and EE optimization problems are discussed taking into account realistic networks operation scenarios. Computational complexity analysis is performed in order to obtain a suitable, yet sturdy, algorithm regarding the robustness versus complexity tradeoff. The performance and complexity of the proposed heuristic approach are compared with a disciplined convex optimization approach based on CvX tools.

A cost effective bidirectional hybrid passive optical network using common carrier for all optical network units (CCAONUs) technique with mitigation of non linearity impact

In this paper, we investigated bidirectional hybrid Wavelength-Division Multiplexing/Time-Division Multiplexing Passive Optical Network (WDM/TDM PON) for mitigation the impact of non linearity like Rayleigh scattering (RS) and Stimulated Brillouin scattering (SBS). The system is constructed cost effective using Common Carrier for All Optical Network Units (CCAONUs). A carrier is engendered at the central office (CO) and remodulated for upstream transmission at the subscriber end making ONU very simple and cost effective. Further, the impact of non linearity is mitigated by phase modulating technique and different wavelengths i.e. 1550nm and 1310nm for upstream and downstream data. It is found that 10 Gbps data can be transmitted and received up to 190 and 185km distance with 256ONUs with minimum acceptable Q factor without any inline amplification respectively.

Performance analysis of different amplifiers for polarization-dependent 10 Gbps bidirectional hybrid WDM/TDM PON with the 16-QAM technique

In this paper, we have investigated bidirectional hybrid wavelength-division multiplexing/time-division multiplexing passive optical networks (WDM/TDM PONs) for Raman amplifiers, semiconductor optical amplifiers (SOAs), and erbium-doped fiber amplifiers (EDFAs) at a 10 Gbps data rate with 128 optical network units (ONUs). The system is improved using polarization modulation with 16 quadrature amplitude modulation (16-QAM) to utilize the maximum bandwidth. A circulator is used to achieve the bidirectional transmission in the same channel. The upstream data is transmitted at 1300 nm and downstream data is transmitted at 1550 nm wavelength so that the crosstalk effect can be minimized. The Q factor and output optical power are measured at 40 and 50 km distance with 128 ONUs for a 10 Gbps data rate. It has been observed that an EDFA shows better performance than a SOA and a Raman amplifier.

AWG-Based Monolithic &lt;inline-formula&gt; &lt;tex-math notation="LaTeX"&gt;$4 \times 12$ &lt;/tex-math&gt;&lt;/inline-formula&gt; GHz Multichannel Harmonically Mode-Locked Laser

We report a novel arrayed waveguide grating (AWG)-based $4\,\times \,12$ GHz multichannel harmonically mode-locked semiconductor laser operating near 1535 nm, which was realized by monolithically integrating a semiconductor optical amplifier (SOA) array, a set of passive optical delay lines, an AWG with 400 GHz channel spacing, a saturable absorber, and a common output SOA. Our device layout and fabrication were completed on the European JePPIX InP photonic integration platform, based on the multiproject wafer run foundry approach. We demonstrated four wavelength channels operating in the fifth harmonic mode-locking regime. Channel repetition rate of 12 GHz and 3-dB RF linewidth as narrow as 6 kHz were obtained. The exhibited performance makes our device a very promising candidate as an ultracompact multichannel light source for future hybrid optical time and wavelength division multiplexing, high-speed photonic analog-to-digital conversion, and optical clock recovery applications.