ESTHER is devoted to the application of soliton transmission to real transport networks, showing that this can be a viable approach to upgrade already installed fibre links to higher bit-rates (10,20 and 40 Gbit/s). As a fallout of the work undertaken, relevant fibre optic components and subsystems will be developed or refined, along with software models for non-linear and linear propagation modelling.
Soliton technology will increase the total capacity of existing networks and overcome detrimental effects like PMD and chromatic dispersion variation. On long distance SI fibre links it will provide an alternative to other methods for dispersion compensation, plagued by narrowband operation and/or high installation costs; its impact on the existing infrastructure will be significant as SI cables are nearly universally used in long-haul trunks.
The exploitation of soliton links in transport networks will profit from the availability on the market of high-speed return-to-zero (RZ) terminal equipment units, whose development will in turn be favoured by the diffusion of the non-linear optical transmission techniques.
ESTHER will provide a testbed for one of the first in-field tests of soliton transmission at 40 Gbit/s. The development of all the components needed for a 40 Gbit/s link (soliton sources, optical MUX/DEMUX units, modulators, receivers etc.) will give EU technology a leading position in a field showing a considerable lag between research and actual use in telecom system engineering.
The ESTHER Consortium's research activity will be addressed to both institutional users (national network operators) and new groups willing to enter the market of long-distance telecommunications after the 1998 liberalisation. The availability of a new technology able to increase the added value of an existing link could be appealing to many potential newcomers, and could represent a significant help in the attempt of establishing a free trade economy in this crucial area.
ESTHER will also contribute to the official standards currently being discussed and relating to the operation of high bit-rate links. The experimental feedback coming from ESTHER will be useful to terminal equipment manufactures willing to integrate RZ transmission features in their systems.
Main contributions to the programme objectives:
A new family of 1.5 mm high-speed soliton transmission systems using step-index (SI) fibre
Contribution to the programme
Satisfies bandwidth demand rapidly and cost effectively on already installed SI fibre networks
ESTHER will exploit innovative soliton sources based on solid state lasers (Er: Ti:LiNbO3) and electroabsorption modulator devices. Innovative approaches to advanced soliton coding (for step-index (SI) fibre transmission) and optical TDM will be pursued using the aforementioned technologies. Terminal units at 10 Gbit/s will be modified for use in soliton links by suitable optimisation of the transmitter-receiver front ends. The field trial cables will be characterised in terms of polarisation mode dispersion (PMD) variations and the robustness of soliton transmission against PMD impairments will be assessed. Operational tests of real traffic transmission will be completed and analysed.
Summary of Trial
Demonstration of 10 Gbit/s soliton transmission over a 500 km step-index (SI) fibre link affected by significant polarisation mode dispersion (PMD) (repeater span 50 km)
Demonstration of 40 Gbit/s soliton transmission over a 500 km dispersion shifted fibre (DSF) link (repeater spacing 80-100 km)
Proof of the feasibility of upgrading an existing 600 km DSF link to 10 Gbit/s by soliton transmission techniques, exploiting non-linear compensation of PMD and chromatic dispersion variations (repeater spacing 100-120 km).
ESTHER will develop most of the field trial activities in Italian infrastructures provided by the local PTT Ministry and by the Italian National Host ITINERA. The project will lead to the completion of a testbed installation (Roma-Pomezia link) upgraded for use in the high-capacity transmission field trial. ITINERA will provide a real connection between ROMA-POMEZIA-LATINA-FORMIA-NAPOLI-NOLA for a total length of 600 km, that will be operated at 10 Gbit/s to show soliton transmission feasibility over long DS fibre cables exposed to "real world" operating conditions and affected by severe PMD impairments.
High frequency control of solid state soliton lasers;
semiconductor device technology;
integration of soliton laser in 10 Gbit/s terminal equipment.
Funding SchemeCSC - Cost-sharing contracts
SO14 3ZH Southampton