H.J.A. da Silva

Development of 10 Gb/s EPON in IEEE 802.3av

The interest in the evolution of current PON systems toward high-data-rate systems capable of providing a future-proof platform for delivery of truly subscriber-oriented and personalized triple-play services resulted in the recent kickoff of the 10 Gb/s Ethernet PON system standardization effort in the IEEE . Ethernet PON has become a network of choice for low-cost subscriber-oriented digital service delivery, taking over the market previously dominated by DSL and cable modems. In this article we examine the current development process of 10 Gb/s EPON systems in more detail, standardized in the framework of the IEEE 802.3av task force, looking at the technical challenges, drivers, and possible evolution scenarios of the emerging high-data-rate access systems..

10G EPON Development Process

The recent kick-off of the 10G EPON system standardization effort in the IEEE [1] resulted in a lot of interest in the evolution of current PON systems towards high data rate systems capable of providing a future-proof platform for delivery of truly subscriber oriented and personalized triple-play services. The Ethernet in the First Mile (EFM) Task Force was disbanded in June 2004, having completed its task of developing and having ratified the IEEE 802.3ah specifications, now merged in the IEEE 802.3-2005 document. The following 2 years saw unprecedented field deployment of EPON systems [2-6], resulting in the currently installed port capacity, estimated at approximately 6 million deployed lines and 15 million ports installed in the Central Office (CO) of Service Providers (SPs) (port numbers valid for March 2007) [1]. Ethernet PON has therefore become a network of a choice for low cost, subscriber oriented digital service delivery, taking over the market previously dominated by DSL and cable modems. In this paper, we will therefore examine in more detail the current development process of 10 Gbit/s EPON systems, standardized in the framework of the IEEE 802.3av Task Force, looking at the technical challenges, drivers and evolution scenarios of the emerging high data rate access systems. Additionally, a brief comparison between EPON and GPON systems is presented, outlining the differences and similarities between these two PON technologies.

FM response of quantum-well lasers taking into account carrier transport effects

The FM response of a single-frequency semiconductor laser is very important for communication systems that use direct modulation of the laser injection current. A new rate equation for the optical phase in quantum-well lasers is proposed, and the corresponding FM response is derived. It is shown that the separate-confinement-heterostructure can have a significant effect on the laser performance. The theory is confirmed with experimental results.<<ETX>>

Radio over fiber access network architecture employing reflective semiconductor optical amplifiers

This paper introduces the RoFnet-Reconfigurable Radio over Fiber network, which is a project supported by the Portuguese Foundation for Science and Technology. This project proposes an innovative radio over fiber optical access network architecture, which combines a low cost Base Station (BS) design, incorporating reflective semiconductor optical amplifiers, with fiber dispersion mitigation provided by optical single sideband modulation techniques. Optical wavelength division multiplexing (WDM) techniques are used to simplify the access network architecture allowing for different Base Stations to be fed by a common fiber. Different wavelength channels can be allocated to different BSs depending on user requirements. Additionally, in order to improve radio coverage within a cell, it is considered a sectorized antenna interface. The combination of subcarrier multiplexing (SCM) with WDM, further simplifies the network architecture, by using a specific wavelength channel to feed an individual BS and different subcarriers to drive the individual antenna sectors within the BS.

Generalized Chu polyphase sequences

The perfect sequences are so ideal that all out-of-phase autocorrelation coefficients are zero. A method to generate a prime number N of perfect sequences with length N is presented. Moreover, these new sets have one more perfect sequence than Chu polyphase sets with the same maximum absolute value of periodic cross-correlation, and are slightly better for asynchronous direct sequence code division multiple access (DS-CDMA). The new sequences are more robust than Chu sequences when used with M-ary quadrature amplitude modulation (QAM). The reason for this improvement is that the new sequences are designed to be orthogonal to the M-ary QAM carriers. Other sequence transformations are also suggested and may be used to obtain many other perfect sequences with the same correlation properties. For example, the new sequences can be transformed into quadriphase sequences, also with good correlation properties.

Discovery process for emerging 10 Gb/s EPONs

Analysis of the techno-economic conditions warranting currently existing deployments of 1 Gb/s (1G) Ethernet passive optical networks indicates clearly the requirement for a support of legacy equipment, allowing carriers to take advantage of already deployed 1G ONUs while increasing the channel capacity for some customers. This calls for a complete coexistence of 1G and 10 Gb/s (10G) equipment, sharing the same physical PON plant. In order to achieve this, a number of technical issues must be resolved in a satisfactory manner, including the required extensions of the discovery process, currently specified in Clause 64 of IEEE 802.3-2008. In this article we present the existing discovery process for 1G-EPON systems and propose a series of extensions required to support the extended discovery process, which include detection of the upstream and downstream data rates, as well as an extension of the existing registration handshake.

On Efficiency of Ethernet Passive Optical Networks (EPONs)

In this paper, we present a detailed and marketing - free study of all components of the upstream and downstream channel transmission overhead for Ethernet Passive Optical Networks (EPONs), excluding optional Forward Error Correction (FEC). First, the general Ethernet framing overhead is evaluated, followed by in depth analysis of each overhead component related to operation of the EPON MPCP protocol. Their overall impact on the performance of the system (especially in the upstream channel) is quantified for both best and worst case scenarios using typical system parameters, characteristic of standard EPON deployments. Based on a set of standard-based and typical EPON parameters, an estimated throughput of approximately 820 to 900 Mbit/s is available in the upstream direction, while in the downstream the effective throughput ranges from around 915 to 935 Mbit/s, producing the channel efficiency figures of 82 to 90% and 91.5 to 93.5% , respectively, relative to the effective data rate of 1 Gbit/s.

Using adapted visibility graphs for network planning

This paper proposes a methodology for planning passive optical networks (PONs) based on the concept of visibility graphs. The said concepts are incorporated in a PON planning tool termed PON builder. The tool accepts AutoCAD maps representing the areas requiring a deployment of a PON and calculates a cost effective fiber layout. When deciding where to place the fiber, PON Builder takes into account the fact that it is cheaper to reuse existing resources than it is to create new ones, that fiber can not be laid through a building and that construction of new resources in spaces such as roads and green-field areas requires higher investment than construction of resources in open space.

Cross-Gain Modulation-based 2R Regenerator Using Quantum-Dot Semiconductor Optical Amplifiers at 160 Gbit/s

This paper presents simulation results of the performance of a 160 Gbit/s 2R regenerator based on Quantum-Dot Semiconductor Optical Amplifiers (QD-SOA). The ultra-fast speed of this device is due to the large Cross-Gain Modulation (XGM) bandwidth of QD-SOAs. A Mach-Zehnder Interferometer (MZI) configuration is used to obtain a non-inverted output signal. Wavelength conversion and 2R (Re-amplifying, Re-shaping) regeneration is demonstrated and several performance issues are discussed.

Performance assessment of two-channel dispersion-supported transmission systems using single- and double-cavity Fabry-Perot filters as demultiplexers

This letter presents a theoretical performance assessment assuming that single- and double-cavity Fabry-Perot filters are used as demultiplexers in two-channel dispersion supported transmission systems operated at 10 Gb/s. A suitable simulation methodology has been used that combines signal simulation with noise analysis in optically amplified multichannel direct detection systems. The results obtained show an improved system performance if a double-cavity Fabry-Perot filter is used as a demultiplexer, resulting in a WDM transmission with a crosstalk power penalty within 1 dB in the region of low dispersion penalty of the DST method, for a channel spacing of 1 nm. The robustness against dependencies on data patterns is verified.<<ETX>>