Objective
Main Objective
The aim of the project is to study signal 3R regeneration in the context of optical fibre communications. The three Rs refer respectively to the three main requirements of regeneration: Reamplifying, Reshaping and Retiming.
In copper-based communication systems, conventional electronic 3R regeneration is a well-known technique to overcome span or bit rate limits. An equivalent regeneration is needed for high bit rate signals carried by optical fibre. In an all-optical network context, the need is even more acute as the optical signal may not only travel over very long distances but also go through many switching nodes. In all these cases, noise and distortion accumulate and full regeneration is necessary to restore clean optical data signals. Finally, optical 3R regenerators as interface devices would ease network interoperability.
Today regeneration may be performed by optoelectronic conversion followed by electronic 3R regeneration. This method is not well adapted to high bit-rate, time and wavelength multiplexed optical signals. Within this project, several new optoelectronic and all-optical 3R regenerators will be considered with two main objectives :
-To assess performances and to compare with present regenerators
-To determine potential strategic advantages of 3R regenerators for optical signals
Technical Approach
Three basic 3R regenerators for optical signals can be considered.
Regenerator Types
All-optical 3R regenerator
The optical data signal is typically split in two. One part is input to an all-optical clock recovery device (mode-locked or self-pulsating laser) which emits a clean train of optical pulses at the bit rate frequency of the data. The all-optical decision circuit uses typically the second part of the data signal to modulate the clean recovered clock signal, which thus becomes the regenerated data. Several devices have been identified for all-optical decision: Q-switched lasers, non-linear interferometers and semiconductor optical amplifiers. The regenerated RZ (Return-to-Zero) optical pulses may be converted to a Non-Return-to-Zero (NRZ) data sequence depending on the data format in the network.
The potential advantages of all-optical 3R regenerators compared to conventional regenerators are a reduced number of elements, integratability, higher speed and no electromagnetic field emission.
Optoelectronic regenerator based on soliton retiming effect
The input train of optical pulses is first transformed into a train of solitons. Those pulses are then modulated by a sinusoidal clock extracted electronically. The signal is then spectrally filtered and sent for non-linear propagation on the output stretch of fibre. Thanks to properties of the non-linear soliton pulses, the above signal processing is equivalent to a 3R regeneration. The potential advantages of 3R regenerators based on soliton effect compared to conventional regenerators are a reduced number of elements, higher speed and the possibility to regenerate a WDM array of signals simultaneously. These regenerators might also handle NRZ optical signals.
Electronic regenerator
The electronic regenerator is similar to conventional regenerators in the detection and re-transmission of the optical signal. The electrical processing is however completely different: it is based on pure digital signal filters based on an unlocked board oscillator.
The potential advantages of the electronic regenerator compared to conventional regenerators are bit rate flexibility and a reduced number of elements. The regenerator will handle NRZ signals.
Summary of Trial
When assembled and tested, the regenerators will be tested on KEOPS, OPEN, METON and HIGHWAY testbeds (AC066, AC043, AC073, AC067) made available respectively by Alcatel Alsthom Recherche, idem, LM Ericsson and British Telecommunications plc.
Expected Achievements
-Fabrication of optoelectronic and electronic devices for reshaping and retiming
-Assembly of 3R regenerators with specially fabricated and commercially available devices
-Definition of specifications and comparison of approaches
-Evaluation of options on testbed
-Dissemination of results and recommendations
Expected Impact
The availability of 3R regenerators able to operate on high bit-rate optical signals would change the vision of future optical networking. Within this project, our main objective will be to assemble 3R regenerators with performances as good as the present electronic solutions. For this a set of specifications will be defined and assembled regenerators measured against these specifications. We will then recommend the best regenerator options, according to potential determining advantages such as: reduction in the number of elements (cost), higher bit rate handling, bit rate flexibility, wavelength transparency, size, etc.
Main contributions to the programme objectives:
Main deliverables
Developed and tested practical solutions for optical signal regeneration.
Contribution to the programme
Comparison of different regeneration technologies for optical networks.
Key Issues
-Optoelectronic devices for all-optical processing based on InP
-High-speed electronic devices based on HEMTs and HBTs
-Simulations and tests of optical fibre systems and networks
Fields of science (EuroSciVoc)
CORDIS classifies projects with EuroSciVoc, a multilingual taxonomy of fields of science, through a semi-automatic process based on NLP techniques. See: The European Science Vocabulary.
CORDIS classifies projects with EuroSciVoc, a multilingual taxonomy of fields of science, through a semi-automatic process based on NLP techniques. See: The European Science Vocabulary.
- natural sciences physical sciences electromagnetism and electronics electromagnetism
- engineering and technology electrical engineering, electronic engineering, information engineering electronic engineering signal processing
- engineering and technology electrical engineering, electronic engineering, information engineering information engineering telecommunications telecommunications networks optical networks
- natural sciences physical sciences optics fibre optics
- natural sciences physical sciences optics laser physics
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Programme(s)
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Multi-annual funding programmes that define the EU’s priorities for research and innovation.
Topic(s)
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Calls for proposals are divided into topics. A topic defines a specific subject or area for which applicants can submit proposals. The description of a topic comprises its specific scope and the expected impact of the funded project.
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Funding Scheme
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Funding scheme (or “Type of Action”) inside a programme with common features. It specifies: the scope of what is funded; the reimbursement rate; specific evaluation criteria to qualify for funding; and the use of simplified forms of costs like lump sums.
Coordinator
91460 Marcoussis
France
The total costs incurred by this organisation to participate in the project, including direct and indirect costs. This amount is a subset of the overall project budget.