R. Bonk

SDN Enabled Dynamically Reconfigurable High Capacity Optical Access Architecture for Converged Services

Dynamically reconfigurable time-division multiplexing (TDM) dense wavelength division multiplexing (DWDM) long-reach passive optical networks (PONs) can support the reduction of nodes and network interfaces by enabling a fully meshed flat optical core. In this paper, we demonstrate the flexibility of the TDM-DWDM PON architecture, which can enable the convergence of multiple service types on a single physical layer. Heterogeneous services and modulation formats, i.e., residential 10G PON channels, business 100G dedicated channel, and wireless fronthaul, are demonstrated co-existing on the same long reach TDM-DWDM PON system, with up to 100xa0km reach, 512 users, and emulated system load of 40 channels, employing amplifier nodes with either erbium-doped fiber amplifiers or semiconductor optical amplifiers. For the first time, end-to-end software-defined networking management of the access and core network elements is also implemented and integrated with the PON physical layer in order to demonstrate two service use cases: a fast protection mechanism with end-to-end service restoration in the case of a primary link failure; and dynamic wavelength allocation in response to an increased traffic demand.

Beneficial OLT transmitter and receiver concepts for NG-PON2 using semiconductor optical amplifiers [invited]

Optical line termination transmitter (Tx) and receiver (Rx) concepts using a semiconductor optical amplifier (SOA) for the next generation of passive optical networks (NG-PON2) are experimentally compared. In general, a single SOA per wavelength channel at the Tx and a configuration comprising a single SOA followed by avalanche photodiodes (APDs) at the Rx are beneficial in terms of signal quality and power dynamic range. Additionally, we introduce a cost-effective bidirectional SOA approach for simultaneous upstream preamplification and downstream boosting. Our results indicate its feasibility for mid-class loss budget classes of NG-PON2.

Demonstration of an SOA-assisted open metro-access infrastructure for heterogeneous services

An open converged metro-access network approach allows for sharing optical layer resources like fibers and optical spectrum among different services and operators. We demonstrated experimentally the feasibility of such a concept by the simultaneous operation of multiple services showing different modulation formats and multiplexing techniques. Flexible access nodes are implemented including semiconductor optical amplifiers to create a transparent and reconfigurable optical ring network. The impact of cascaded optical amplifiers on the signal quality is studied along the ring. In addition, the influence of high power rival signals in the same waveband and in the same fiber is analyzed.

Amplification of advanced modulation formats with a semiconductor optical amplifier cascade.

The convergence of optical metro networks and access networks extends the area of network coverage, and therefore requires the use of optical amplifiers. For this purpose, semiconductor optical amplifiers (SOA) would be attractive, because they are broadband, can be centered between 1250 nm and 1600 nm, and because they are cheap in production and operation. We show that signals encoded with advanced modulation formats such as BPSK, QPSK, 8PSK, and 16QAM can be amplified by a cascade of at least four SOAs. This enables high-capacity paths with a capacity in the order of Tbit/s for converged metro-access networks.

Ultra-Dense, Single-Wavelength DFT-Spread OFDMA PON With Laserless 1.2 Gb/s ONU Ready for Silicon Photonics Integration

We introduce an ultra-dense network architecture designed for silicon photonics at the optical network unit (ONU). This network relies on only 3.333 GSa/s and 417 MSa/s converters at the OLT and ONU, respectively, and offers up to 12 Gbit/s of symmetric traffic in a single 12.5-GHz optical channel. Multiple access and lowest processing speeds at the ONU are enabled by choosing 10 DFT-spread OFDM subbands. We demonstrate this FDMA network architecture in a proof-of-principle experiment with up to eight 300-MBd 16QAM subbands offering a bidirectional data rate of 9.6 Gb/s. Real-time signal processing is realized for downstream transmission. Finally, we shortly address future improvements of this network architecture by employing integrated silicon photonics and analog signal processing to enable fine FDM for next-generation access networks.

Cross-talk analysis & mitigation for TWDM-PON upstream path

Various cases of cross-talk mechanisms occurring in a TWDM-PON are analyzed in simulations and experiments. Power penalty degradations and limitations of photonic component technologies are described and mitigation techniques enabling such NG-PON2 systems are introduced.

Access and metro network convergence for flexible end-to-end network design [invited]

This paper reports on the architectural, protocol, physical layer, and integrated testbed demonstrations carried out by the DISCUS FP7 consortium in the area of access–metro network convergence. Our architecture modeling results show the vast potential for cost and power savings that node consolidation can bring. The architecture, however, also recognizes the limits of long-reach transmission for low-latency 5G services and proposes ways to address such shortcomings in future projects. The testbed results, which have been conducted end-toend, across access–metro and core, and have targeted all the layers of the network from the application down to the physical layer, show the practical feasibility of the concepts proposed in the project.

Wavelength-transparent long-reach-high-split TWsDM-PON utilized by a non-gated parallel cascade of linear SOAs

We demonstrate the first long-reach and high-split TWsDM-PON utilizing a non-gated parallel cascade of linear SOAs. A fiber reach of up to 100 km and up to 2048 customers are achieved in non-wavelength routed outside plants.

Embedded OTDR measurement range extension for future metro-access networks employing in-line SOAs

We demonstrate for the first time the measurement range extension of an embedded OTDR system employing SOA within the fiber network. eOTDR monitoring across multiple SOA-amplified fiber segments with simultaneously GPON downstream transmission is achieved.

Ultra-dense, single-wavelength DFT-spread OFDM PON with laserless 1 Gb/s ONU at only 300 MBd per spectral group

We demonstrate an FDMA network with up to eight 300 MBd 16QAM subcarriers offering bidirectional 9.6 Gbit/s within a single 12.5 GHz channel. OLT and ONU operate at only 3.2 GSa/s and 400 MSa/s, respectively. Real-time signal processing is realized for downstream transmission.