The primary objective of the project is to demonstrate 40 Gbit/s transmission over currently installed optical fibre lines at 1.55 um. To achieve this primary goal, two complementary objectives have been defined for the project:
Investigation and development of non-linear soliton propagation techniques at 40 Gbit/s for a field trial over Dispersion Shifted Fibre (DSF) lines
Investigation and development of linear transmission techniques to undertake a field demonstration of the capability of 40 GHz transmission over standard fibre lines.
Primary achievements for the first part of the project include:
Preliminary linear field trial using MSSI achieving 10 Gbit/s RZ data transmission at BER of 10-11 over 140 km of installed fibre.
Characterisation of DSF lines for soliton field trial and establishment of sub-systems for testbed.
Preliminary design and specification for 40 Gbit/s electronic receiver
Development of advanced soliton propagation methods beyond 40 Gbit/s utilising loss-compensating dispersion-decreasing fibre (LCDDF).
The overall expected achievement is the demonstration of the limitations and performance of 40 Gbit/s optical transmission technology over existing fibre lines. The development activities will evaluate and provide methodology to assess the future capability and impact of systems beyond 40 Gbit/s. Supported by the advanced technology aspects of the project a meaningful comparison of the transmission methods can be undertaken.
The project provides a practical demonstration of high capacity (40 Gbit/s) transmission over two types of currently installed fibre lines. The expected impact will be the demonstration of the potential capability to upgrade existing fibre networks for higher capacity operation. The advanced communications work will support the 40 Gbit/s transmission evaluation by providing indications of the limitations for high capacity transmission beyond 40 Gbit/s in existing and future installations.
Main contributions to the programme objectives:
Demonstrated a 40 Gb/s soliton transmission on currently installed optical fibre.
Contribution to the programme
Upgraded existing fibre networks to higher transmission capacities
The structure of the project has been designed to provide advanced demonstration of 40 Gbit/s transmission, whilst accommodating development activities to support the advanced technology and investigate concepts for transmission beyond these rates.
The soliton work is focused toward the development of an advanced testbed facility for full system evaluation prior to demonstration over installed DSF lines. The system will utilise an all-fibre transmitter to generate the soliton stream at 10 Gbit/s and multiplex using a 4 x 10 Gbit/s multiplexer. The receiver will consist of an optical demultiplexer converting 40 Gbit/s to 10 Gbit/s data stream and an electronic 10 Gbit/s receiver. In support of the system developments, soliton control techniques are under investigation together with advanced high speed materials developments.
The linear transmission work is based on the use of Mid-span spectral inversion (MSSI) to compensate for the fibre dispersion. The limitations of the technique are being assessed both theoretically and experimentally prior to demonstration on installed lines. An integral part of the work is the development of the EFRL source and associated optical time-division multiplexing (OTDM). The field experiments will demonstrate 40 Gbit/s data transmission.
In support of both these activities will be:
The development of a polarisation mode dispersion (PMD) measurement system to provide spatial information of the fibre birefringence.
The development of a 40 GHz receiver front end to enable direct 40 Gbit/s detection.
The primary objective of the project is to demonstrate 40 Gbit/s transmission. However, in order to understand both the sub-system and system limitations, the advanced concepts part of the project is targeted at investigating potential techniques to operate beyond 40 Gbit/s.
Summary of Trials
Two demonstrations of 40 Gbit/s transmission over currently installed fibre lines will be undertaken.
The soliton field trial will be undertaken over DSF lines installed in the Jonkoping ring in Sweden, and provided by Telia as part of the Swedish National Host. Initially an advanced, high speed measurement testbed utilising DSF fibre will be established to evaluate the subsystems developed. The elements of the transmission system for the field trial will initially be integrated within the testbed, to enable the full evaluation of the system within the laboratory environment prior to measurements over the installed lines. In addition the testbed will be used to evaluate advanced concepts for possible introduction into the field trial and examination of transmission limitations beyond 40 Gbit/s. Following integration and laboratory evaluation the system will be transferred to access fibre lines from the Swedish network and the 40 Gbit/s soliton transmission experiments undertaken to compare with results obtained from the laboratory testbed.
The linear field demonstration will be undertaken within the Italian National Host. The trial will be undertaken in the Torino area. The 140 km link will consist of four lines spanning Torino to Cirie via Caselle, enabling the transmitter, receiver and mid-span spectral inversion system to be accommodated at the same location. A preliminary trial has been undertaken and successfully demonstrated 40 GHz pulse transmission over standard fibre lines using MSSI and also 10 Gbit/s BER measurements. The full trial to be undertaken over these lines later in the project will demonstrate full 40 Gbit/s transmission.
Two 40 Gbit/s transmitters, different designs, based on fibre ring lasers and OTDM
Optical clock recovery and demultiplexer to 10 Gbit/s
Development of 40 GHz receiver front end
Development of spatial PMD measurement system for fibre line evaluation
40 Gbit/s transmission measurements
High speed non-linear materials for soliton control and MSSI
Demonstration and comparison of linear and soliton transmission at 40 Gbit/s.
Funding SchemeCSC - Cost-sharing contracts
SO14 3ZH Southampton