Jörg-Peter Elbers

PON in adolescence: from TDMA to WDM-PON

Passive optical networks are used for fiber-to-the-home/curb/cabinet/building applications. Today, two PON variants with time-domain multiple access, GPON and EPON, are being used for mass roll-outs. WDM-PONs are the next step up from these PONs to accommodate traffic growth and new applications. This article analyzes WDM-PON variants and proposes they be used for a unified optical access and back-hauling network.

Cost and energy consumption analysis of advanced WDM-PONs

Next-generation access systems will have to provide bandwidths in excess of 100 Mb/s per residential customer, in conjunction with high customer count and high maximum reach. Potential systems solutions include several variants of WDM-PONs. These systems, however, differ significantly in their cost (capital expenditures) and energy consumption potential. We compare several WDM-PON concepts, including hybrid WDM-PON with integrated per-wavelength multiple access, with regard to these parameters. We also show the impact and importance of generic next-generation bandwidth and reach requirements.

Adaptive Data Rates for Flexible Transceivers in Optical Networks

Efforts towards commercializing higher-speed optical transmission have demonstrated the need for advanced modulation formats, several of which require similar transceiver hardware architecture. Adaptive transceivers can be built to have a number of possible operational configurations selected by software. Such software-defined transceiver configurations can create specific modulation formats to support sets of data rates, corresponding tolerances to system impairments, and sets of electronic digital signal processing schemes chosen to best function in a given network environment. In this paper, we discuss possibilities and advantages of reconfigurable, bit-rate flexible transceivers, and their potential applications in future optical networks.

Coarse WDM/CDM/TDM concept for optical packet transmission in metropolitan and access networks supporting 400 channels at 2.5 Gb/s peak rate

To improve the networking flexibility in the metropolitan and access area, the granularity in the optical domain has to be increased above that in the core network requiring more channels at lower bit rates. Pure dense wavelength division multiplexing (DWDM) as it is applied in the core does not seem to meet this requirement at affordable cost. We propose and analyze a network based on hybrid optical multiplexing techniques including wavelength, code, and time division multiplexing. Applied to optical packet transmission this approach enables several 100 all-optical channel between end users and headend with average bit rates up to 100 Mb/s per channel while keeping the installation and maintenance cost at a minimum.

Access Networks Based on Tunable Lasers

State-of-the-art, prospects, and challenges of next-generation optical access technology based on tunable lasers are discussed. These considerations can also be applied to various backhaul and mobile fronthaul applications since these have similar characteristics and requirements, and have to share at least part of the optical distribution networks. Potential advantages of tunable lasers over competing approaches (e.g., seeded reflective transmitters) include higher bit-rate × reach products and better tolerance to reflections in the fiber plant. Today, the main issue is still the lack of available low-cost tunables with sufficient tuning range and launch power. However, significant progress has been made in the last few years to bring such lasers closer to commercialization. In this paper, we will review low-cost tunable laser approaches and report on latest technical results. We will also give an overview on current standardization activities and give an outlook on next-generation optical access, backhaul and fronthaul networks which also support active-site consolidation.

DMT Modulation With Adaptive Loading for High Bit Rate Transmission Over Directly Detected Optical Channels

In this paper, we present the design and analysis of an adaptive cost-effective discrete multitone transponder (DMT) using direct detection (DD) suitable for data center interconnections. Levin Campello margin adaptive (LC-MA) algorithm is applied to the transponder digital signal processing modules to enhance fiber chromatic dispersion (CD) resilience, while achieving high-data rate transmission. The bit error rate (BER) performance and the rate/distance adaptive capabilities of the proposed transponder have been numerically analyzed and compared to bandwidth variable uniform loading, taking into account the transmission impairments at the varying of the fiber length. Specifically, the performance of the designed transponder has been assessed from 20 to 112 Gb/s, extending the achievable reach at 50 Gb/s beyond 80 km of standard single mode fiber (SSMF). The numerical simulations have been compared with experimental results, evidencing good agreement in presence of transmission impairments.

From static to software-defined optical networks

Software-defined optical transceivers, a fully programmable optical express layer, and control plane-assisted network automation are key constituents of a new generation of optical core networks. This paper explains enabling technologies, reviews emerging applications, and discusses new questions arising for network design and modeling. It also examines the integration of the optical wavelength with the OTN and MPLS layers.

PON Evolution from TDMA to WDM-PON

WDM-PONs are the next step from todays EPONs/GPONs to accommodate further traffic growth and facilitate new applications. WDM-PON variants are analyzed and proposed as solution for a unified optical access and backhauling network.

Field trial of a quantum secured 10 Gb/s DWDM transmission system over a single installed fiber

We present results from the first field-trial of a quantum-secured DWDM transmission system, in which quantum key distribution (QKD) is combined with 4 × 10 Gb/s encrypted data and transmitted simultaneously over 26 km of field installed fiber. QKD is used to frequently refresh the key for AES-256 encryption of the 10 Gb/s data traffic. Scalability to over 40 DWDM channels is analyzed.

First field demonstration of cloud datacenter workflow automation employing dynamic optical transport network resources under OpenStack and OpenFlow orchestration

For the first time, we demonstrate the orchestration of elastic datacenter and inter-datacenter transport network resources using a combination of OpenStack and OpenFlow. Programmatic control allows a datacenter operator to dynamically request optical lightpaths from a transport network operator to accommodate rapid changes of inter-datacenter workflows.