F. Saliou

Things You Should Know About Fronthaul

This paper provides a review of the new fronthaul network segment that appears in centralized radio access network (C-RAN) architecture. C-RAN drivers are presented under an operational, economic, and radio point of view. The different fronthaul interfaces are briefly described as they have to be taken into account to build a fronthaul transport solution. Then, fronthaul requirements are detailed going from the technical ones to the business ones. Finally, different fronthaul solutions are presented. Perspectives for medium term evolution including fronthaul supervision are hinted as well as challenges for future mobile evolution toward 5G.

Reach Extension Strategies for Passive Optical Networks [Invited]

We present here the main results for reach extension in passive optical network (PON) technologies. Both passive and active architectures integrating several multiplexing techniques are studied, and they provide promising results for the future generation of optical access networks. Extender boxes based on optical amplification and optical-electrical-optical (OEO) repeaters are evaluated over a standardized gigabit PON (GPON) system. With this architecture, the optical budget of a class B+ access network can be increased so as to achieve a total budget of 65 dB. Furthermore, using the technique of remotely pumped optical amplification on a wavelength division multiplexing/time division multiplexing (WDM/TDM) topology, the optical budget of a class C+ PON tree could be increased by an additional 22 dB amounting to a total budget of 55 dB. These results are promising since they should enable high flexibility on the optical budget to achieve more reach and splitting ratio, which are prerequisites needed for the migration to the next-generation access networks.

Investigation into optical technologies for access evolution

This paper considers the main technical challenges for optical access network deployment. Technological evolution of broadband optical networks is discussed with the need for adapting both metropolitan and access networks to the customer services demand evolution.

Demonstration of a Remotely Dual-Pumped Long-Reach PON for Flexible Deployment

We propose and experimentally demonstrate a flexible wavelength division multiplexing/time division multiplexing network architecture for converged metro-access environment. Entire passiveness in the fiber plant is achieved with remote amplification in the signal distribution nodes along the metro ring and in the power splitters of the local access tree. We assist a traditional remote pumping scheme with a distributed pump provided by the optical network units and demonstrate that loss budgets beyond 30 dB can be supported. Data transmission of up to 10 Gb/s is evaluated in different deployment scenarios, reaching from a 78 km long reach rural to a dense 1:128 split/λ urban configuration with field installed fibers, including also worst case resilience configurations.

Things you should know about fronthaul

After introducing fronthaul requirements in Centralized Radio Access Network architecture, different fronthaul solutions are presented. Perspectives for medium term evolution including fronthaul supervision are hinted as well as challenges for future mobile evolution towards 5G.

C- and O-band operation of RSOA WDM PON self-seeded transmitters up to 10 Gb/s [Invited]

We propose a network-embedded colorless self-tuning transmitter for wavelength division multiplexed (WDM) networks based on self-seeding in reflective semiconductor optical amplifiers (RSOAs). We compare up to a 10-Gb/s data rate in either O-band or C-band operation. In particular, the transmitter exploits a two-Faraday rotator configuration to ensure polarization-insensitive operation and allowing for the exploitation of high-gain C- and O-band RSOAs, which present a very high polarization-dependent gain. Two different multiplexers and various lengths of drop fibers constituted the network-embedded transmitters in order to evaluate various dispersion load influence on cavity buildup. Moreover, transmission over standard single-mode feeder fiber has been evaluated both at 2.5 and 10 Gb/s to compare the performance in both bands, confirming the absence of chromatic dispersion penalties for the O-band operation.

10-Gb/s Operation of a Colorless Self-Seeded Transmitter Over More Than 70 km of SSMF

Operation of a network-embedded colorless self-tuning transmitter for wavelength division multiplexing (WDM) networks is experimentally demonstrated at 10-Gb/s data rate. Colorless operation is achieved by self-seeding an O-band reflective semiconductor optical amplifier (RSOA) with the feedback signal reflected at the remote node WDM multiplexer filter. In particular, the transmitter exploits a 2-Faraday rotators configuration to ensure polarization insensitive operation and allowing for the exploitation of high gain O-band RSOAs, which present a very high polarization dependent gain. Two different multiplexers and various lengths of drop fibers constituted the network-embedded transmitters. Transmission up to 72 km of standard single mode fiber has been demonstrated at 10 Gb/s, confirming the absence of chromatic dispersion penalties as expected from the choice of the O-band operation.

Self-seeded RSOA based WDM-PON transmission capacities

A self seeded WDM PON solution is evaluated at 1.25Gb/s and 2.5Gb/s in order to address optical budget, rise and fall time and jitter performances issues.

Single SOA to extend simultaneously the optical budget of coexisting G-PON and 10G-PON

A wide-band SOA is used for amplification of both downstream signals from G-PON and 10G-PON access networks. BER measurements showed a performance of 42dB on optical budget but also pointed out requirements on the SOA to improve this performance.

Self-tuning transmitter for fibre-to-the-antenna PON networks

WDM PONs offering point-to-point connectivity, independence of multiple access protocol to share the medium are good candidates for supporting the new fronthaul fibre network requirements. The necessity to allow inventory and maintenance cost reduction will favour WDM PON solutions based on colourless transceivers. We present the proposal of a network embedded self-tuning colourless transmitter, based on reflective semiconductor optical amplifier (RSOA) self-seeding architectures. We analyse the fibre-to-the-antenna network requirements and evidence the capabilities of the network embedded self-tuning colourless transmitter, showing its principle of operation, the development and the modelling of the active elements. We present and discuss recent experimental results up to 10Gbit/s, which are encouraging for the transmitter exploitation in fronthaul WDM multiplexing technology.