Evolution Of Passive Optical Networks Research Articles

Photonic Integrated Circuits for Passive Optical Networks: Outlook and Case Study of Integrated Quasi-Coherent Receiver

Photonic Integrated Circuits (PICs) are taking a major role in the telecommunications and datacenter markets. The increased complexity of coexisting and fast evolving standards for Passive Optical Networks (PONs) suggests the introduction of PICs will be the next step in PON related optoelectronics. The PICs ecosystem has greatly matured in the past years, becoming a solution that can cope with the requirements of industry and academia, and presenting the flexibility of combining multiple platforms available towards viable commercial solutions. In this review, the evolution of PONs and PICs is presented, with a focus on the optoelectronic integration of PICs for PONs and coherent PONs. To demonstrate the potential of PICs and their combination with electronics, a quasi-coherent receiver based on co-hosted PIC and Application Specific Integrated Circuit (ASIC) is presented and characterized.

A smooth PON evolution based on PAM4 complement code

We propose a smooth evolution of passive optical network (PON) based on PAM4 complement code (PCC). In PCC, a PAM4 symbol is added after every-three binary bits to complement them so the code efficiency of PCC is 75%. The PCC based PON evolution is demonstrated and tested by simulation. The tested results verify the feasibility of the proposed PCC based PON evolution. The reception for PCC is traditional binary reception (not PAM4 reception). Compared with widely applied Manchester code, PCC shows almost the same performance while the code efficiency is increased to 75%. Compared with 6b8b code whose code efficiency is also 75%, PCC shows much better performance.

Introduction to the JOCN special issue on future PON architectures enabled by advanced technology

This JOCN Special Issue, which spans the September and October 2020 issues, investigates the future of passive optical networks (PONs) in light of new enabling technologies that are currently under consideration. The papers present a broad overview of topics of current interest, across both the physical and network layers. They investigate how new technologies (e.g., higher-speed direct detection transceivers, coherent systems, advanced digital signal processing, and new optoelectronic components) and new network-layer approaches may drive the medium- to long-term evolution of PONs.

Grant-sizing-differentiated bandwidth allocation algorithm for the coexistence of ONUs with and without wavelength tunability in WDM/TDM PONs

Adopting the pay-as-you-grow approach to upgrade passive optical network (PON) facilities by WDM technology insures the smoothness of the upgrade, and also results in the coexistence of wavelength-fixed/tunable optical network units (ONUs) in WDM/TDM PONs. Dynamic bandwidth allocation (DBA) is the key to support such coexistence of heterogeneous ONUs. Thus, DBA is also the key to support the smooth evolution of PONs. To more fairly coordinate the bandwidth allocation among the coexisting heterogeneous ONUs, a differentiated grant sizing (DGS) scheme is proposed. In DGS, not only the fairness between the wavelength-fixed/tunable ONUs but also the fairness between the lightly/heavily loaded ONUs is taken into account. To further carry out load balancing among wavelengths, a grant scheduling scheme is also proposed to cooperate with the grant sizing scheme. In the grant scheduling scheme, a measure of the ONUs’ flexibility is given, and then the least flexible job first rule (LFJF) is adopted for joint wavelength and time-slot assignment. Finally, to demonstrate the effectiveness of the proposed algorithm, a series of comparative analyses is conducted based on simulation experiments.

PON Roadmap [Invited

With the recent conclusion of the XGS-PON and NG-PON2 standards in the ITU-T, the fiber access industry is now considering where to go next. This paper reviews the passive optical network (PON) systems market and the services that will drive the take-up of these next-generation PON technologies. The drivers for future PON evolution are discussed, and some technology options for the evolution of PON systems are highlighted.

EFFECT OF CHANNEL SPACING ON THE SIGNAL QUALITY FOR A BI-DIRECTIONAL TWDM PON

As the demand for broadband services increase coupled with the introduction of new services like online interactive gaming, high definition video TV, video on demand etc., the ability to support higher data rates and efficient utilization of the deployed network is necessary. This largely depends on the capacity and quality of the access networks. Currently deployed Passive Optical Networks (PON) like GPON and EPON will not be able to meet the growing demand in the future. Although both of these PONs have evolved to their respective 10G versions called XG-PON and 10G-EPON, they will eventually reach the limit of their capacity. This has paved the way for the next evolution of PON named as Next Generation PON Stage-2 (NG-PON2). NG-PON2 has the advantage of a much larger bandwidth and scalability by using a combination of Time and Wavelength Division Multiplexing known as TWDM PON. In this paper we have investigated the effect of varying channel spacing (50GHz, 100GHz and 200GHz) on the quality of a Bi-directional TWDM PON signal. The best results were obtained with the widest channel spacing of 200GHz (1.6nm).

A Smooth Evolution to Next Generation PON Based on Pulse Position Modulation (PPM)

A smooth evolution of passive optical networks (PONs) is proposed, which realizes an upgrade link coexisting with the existing link by pulse position modulation (PPM). In the evolution, the optical distribution network and existing optical network units remain with no changes. The coexisting brings in crosstalk from the upgrade PON link to the existing PON link. The crosstalk is reduced by PPM because PPM provides good suppression at low frequency and high receiving sensitivity. The coexisting scheme is experimentally demonstrated and error free operation is achieved for both the existing signal and the upgrade signal. The tested power penalty of the existing signal coexisting with the upgrade signal in PPM is ~0.5 dB, better than Manchester code, which has been considered as the best candidate for upgrade signal modulation. Taking code efficiency into consideration, the PPM with four pulse positions (4PPM) shows the best performance in the coexisting evolution.

Passive-Optical-Network- (PON-) Based Converged Access Network [Invited

This paper describes an evolution of passive optical network (PON) technology deployment, which has primarily focused on residential markets, with triple play services consisting of voice, data and video, towards the support of a high value Ethernet and optical business services, with a vision of having a converged PON-based access network for all residential and business services. Business services, including wireless backhaul, are key components of a service provider portfolio, and use of the PON centric access network allows for more optimized deployment of these services. The paper also presents architectural approaches for supporting various types of business services over a PON-based fiber-to-the-premises network.

Evolution of Optical Access Networks: Architectures and Capacity Upgrades

Passive optical network (PON) is one of the most successful broadband access architectures being deployed worldwide. PONs provide high capacity, increased reach, and low-power consumption at a very reasonable cost, on par with the cost of DSL deployments today. This paper provides an overview of present and emerging PON technologies, and discusses PON's important role in the evolution of optical access from the architectural perspective. While describing the evolution of optical access architecture, we present two important integration options: optical+wireless access integration and metro+access integration. Potential PON capacity upgrades are discussed with special emphasis on achieving a seamless upgrade. We evaluate different PON evolution strategies in the context of next-generation PON, where gradual, demand-based migration demonstrates a number of significant benefits.

Evaluating strategies for evolution of passive optical networks

Rapidly-increasing traffic demands will require the upgrade of optical access networks, namely deployed Passive Optical Networks (PONs), which may soon face capacity exhaustion. Such upgrade options must consider several technical and cost factors for evolution toward a shared multiple-channel PON using Wavelength- Division Multiplexing (WDM). WDM can facilitate the seamless upgrade of PONs, since capacity can be increased by adding new wavelength channels. We study the requirements for optimal migration toward higher bandwidth per user, and examine scenarios and cost-effective solutions for PON evolution.

A passive network termination for BISDN optical subscriber lines

Considerable cost saving and overall simplification can be achieved if the protocol for the access digital section is made identical to the one at the T interface. The network termination (NT1) may then be realized as a passive device, such as a simple connector. All active functions associated with the NT1 can then be performed on a time-shared basis from the premises of the network provider. This scheme obviates the need for remote power feeding and activation mechanisms of the NT1. The time sharing of active functions, such as optical time domain reflectometry (OTDR) for supervision of the physical conditions of the lines, allows a substantial cost reduction of the subscriber access. It is shown that this technique yields a more efficient maintenance scheme than that afforded by an active NT1, resulting in a cost saving also in the long term. Ways of implementing the passive NT1 are discussed, and also its position in the evolution of passive optical networks (PON) towards BISDN.