Hybrid Passive Optical Networks Research Articles

Protection Schemes in HPON Networks Based on the PWFBA Algorithm.

In this paper, possibilities for network traffic protection in future hybrid passive optical networks are presented, and reasons for realizing and utilizing advanced network traffic protection schemes for various network traffic classes in these networks are analyzed. Next, principles of the Prediction-based Fair Wavelength and Bandwidth Allocation (PFWBA) algorithm are introduced in detail, focusing on the Prediction-based Fair Excessive Bandwidth Reallocation (PFEBR) algorithm with the Early Dynamic Bandwidth Allocation (E-DBA) mechanism and subsequent Dynamic Wavelength Allocation (DWA) scheme. For analyzing various wavelength allocation possibilities in Hybrid Passive Optical Networks (HPON) networks, a simulation program with the enhancement of the PFWBA algorithm is realized. Finally, a comparison of different methods of the wavelength allocation in conjunction with specific network traffic classes is executed for future HPON networks with considered protection schemes. Subsequently, three methods are presented from the viewpoint of HPON network traffic protection possibilities, including a new approach for the wavelength allocation based on network traffic protection assumptions.

Performance Analysis of Hybrid Optical Amplifier for Hybrid Passive Optical Networks

Performance Analysis of Hybrid Optical Amplifier for Hybrid Passive Optical Networks

Investigation of Performance Affecting Parameters on Hybrid Passive Optical Networks

AbstractIn the evolvement of current passive optical networks (PONs), there is ever increasing bandwidth demand due to dynamic service requirements. This introduces challenge for the choice of multiplexing technique and physical layer bounds like fiber length, data rate, and number of users are critical over a suitable architecture. In this article, hybrid wave division multiplexing-time division multiplexing PON is analyzed using variable length of fiber with data rates up to 40 Gbps over a maximum of 128 end users. Comparative study using different frequency spacing’s has shown that it has negligible effect on the Q-factor performance parameter. Further in the work, variable data rates required for different services is successfully transmitted up to 30 km to 128 number of users for an acceptable level of bit error rate.

Performance Analysis of Different Electrical Filters in 10G Hybrid Passive Optical Network

With growing number of applications and network traffic, optic fibers are extensively used in the access part of the network. Passive Optical Networks (PON) in particular, Ethernet PON (EPON) networks based on Time Division Multiple Access (TDMA) are more prominently used in many parts of the world. Though Wavelength Division Multiplexing (WDM) PON has its own advantages, considering the cost and utilisation of such networks in the access part makes it less useful. On the other hand, Hybrid PON network combines the advantages of both EPON and WDM PON Networks. The objective of this paper is to identify suitable electrical filters for a 16-channel Hybrid Passive Optical Network with a transmission rate of 10Gbps per channel, by analysing their performance in terms of Q factor and Bit Error Rate. Different filters like the Bessel filter, Gaussian filter, Raised Cosine Filter, Rectangular filter, Butterworth filter, Chebyshev Filter are compared and their performances are evaluated. DB Modulation format that provides a longer reach is used at the transmitter to evaluate the different scenarios and the simulation is carried out using Optisystem.

Survivable Hybrid Passive Optical Converged Network Architectures Based on Reflective Monitoring

Hybrid passive optical converged access networks (HPCANs) are recognized as a cost-efficient and high-bandwidth solution to address the exponentially increasing demands of both fixed access and mobile users. HPCANs are expected to support high client count with different bandwidth requirements, long network spans, and high traffic. In that respect, survivability of such networks against fiber/equipment failures is a critical deployment feature. Consequently, rapid fault detection and subsequent restoration of services to users are gaining importance. Four survivable architectures that are compliant with the aforementioned HPCAN specifications are presented in this work. These architectures do not need to rely on upstream transmissions for loss-of-signal (LOS) activation, thereby making them suitable for use with sleep/doze mode transceivers for power saving. In networks that implement sleep/doze upstream transceivers, the transition into sleep/doze mode would result in no upstream signal transmission. If using conventional LOS activation rather than our proposed architectures to indicate equipment/fiber failure in the network, the absence of upstream transmission would result in erroneous triggering of false LOS alarm and subsequently unnecessary protection switching. We compare the four survivable HPCAN architectures against an unprotected HPCAN using illustrative examples of three different population densities, namely covering dense urban, urban, and rural areas, and three different deployment scenarios, namely brownfield, duct reuse, and greenfield. We perform detailed evaluations of connection availability, failure impact factor, yearly network energy consumption, and total network cost. Results from this study provide guidance for the choice of the best survivable HPCAN architecture to serve each of the three considered area densities under each of the three deployment scenarios.

A novel architecture of hybrid (WDM/TDM) passive optical networks with suitable modulation format

In this paper, we have analyzed the performance and feasibility of a hybrid wavelength division multiplexing/time division multiplexing passive optical network (WDM/TDM) PON system with 128 optical networks units (ONUs). In the proposed network, the triple play services (video, voice and data) are successfully transmitted to a distance of 28km to all ONUs. In addition, we investigate and compare the proposed hybrid PON for suitability of various modulation formats for different distance. It has been observed that the most suitable data format for hybrid PON network is NRZ Rectangular.

Rayleigh Scattering Tolerant PON Assisted by Four-Wave Mixing in SOA-based ONUs

A scheme for the mitigation of Rayleigh backscattering (RB) in hybrid passive optical networks (PON) is presented. Semiconductor optical amplifiers (SOA) of the optical network units (ONU) are advantageously used as nonlinear elements, exploiting Four-Wave Mixing (FWM) between the downstream signals to create a spectrally displaced optical upstream carrier. The proposed technique is experimentally proven in a long reach and high split PON, and the suppression of the pumps and further FWM products, obtained via a modified filtering scheme inside the PON, is analyzed. Full-duplex transmission at 10/2.5 Gb/s is demonstrated, showing that upstream transmission is possible despite low optical signal-to-RB ratios (OSRR) of ~ 12 dB.

Rayleigh Noise Mitigation Using Single-Sideband Modulation Generated by a Dual-Parallel MZM for Carrier Distributed PON

Hybrid passive optical networks (PONs) with a centralized light source (CLS) could be a promising solution for the next-generation PON. However, the network with a loop-back architecture will give rise to interferometric noise caused by Rayleigh backscattering (RB). Here, we propose and demonstrate a colorless optical networking unit (ONU) using a dual-parallel Mach-Zehnder modulator (DP-MZM) to mitigate RB noise in a hybrid wavelength-division-multiplexing-time-division-multiplexing PON with CLS. Both dominant contributions of RB, carrier RB and signal RB, are experimentally characterized, for the first time, when using a DP-MZM as a reflective ONU. In addition, the split-ratio of a long-reach PON using the DP-MZM-based ONU is also investigated and analyzed, showing RB noise can be efficiently reduced.

Monitoring technique for a hybrid PS/WDM-PON by using a tunable OTDR and FBGs

A monitoring technique for hybrid passive optical networks (PON) is presented. The technique is based on the remote sensing of fibre Bragg gratings (FBGs) using a tunable optical time domain reflectometer (OTDR). The FBG would help discern an individual event during the monitoring of the hybrid PON in collaboration with the information provided by the Rayleigh backscattered power. The hybrid architecture of passive splitter-PON and WDM-PON can be analysed by the monitoring method by using the tunable OTDR and FBGs at the central office under the in-service state of PON.