Mots-clé
(Anglais)
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fiber characterization; distributed measurements; fiber monitoring; quantum communication
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Programme de recherche
(Anglais)
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COST-Action 299 - Optical Fibres for New Challenges Facing the Information Society
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Description succincte
(Anglais)
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The main goal is to use a new photon counting detector technology, with a lower jitter, to develop a photon counting Optical Time Domain Reflectometer (nu-OTDR) with a resolution of a few centimeters which has a higher resolution than current apparatus. The improved performances of this device will pave the way for a new class of optical fibre sensing which requires high sensitivity and high resolution. The second target is to continue and enlarge our investigation on photonic fibre properties which commenced with COST P11.
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Partenaires et organisations internationales
(Anglais)
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BE, CH, CY, CZ, DE, DK, ES, FI, FR, GR, HR, IE, IL, IT, PL, PT, RO, SE, SK, UK
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Résumé des résultats (Abstract)
(Anglais)
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Starting from telecommunication and sensoring to imaging and even medical applications, optical fibers get more and more important in very different domains of science and daily life.To find the optimal solution or to extend the areas of application, progresses in design and fabrication are aspired. Before new designs can be comercialized it is important to characterize the fibers properties. Not less important is the analysis of already (sometimes 20 years ago) installed fibers, for example in telecommunication networks, in order to infer their compatibility concerning data rate upgrades. We concentrate our work on the characterisation of fibers, in particular using techniques based on single photon counting (InGaAs and Si avalanche photodiodes (APD)). Single photon counting delivers high sensitivity and still yields results when classical techniques reach their limits. We are concerned with the steady improvement of this technique. One goal is to significantly decrease the measurment time, to acquire data with sufficiently large statistics. The dominating limitation in InGaAs-APD based single photon detection is the afterpulsing effect. Here, we succeded in implementing a scheme called 'rapid gating', where the detection of very weak avalanches is possible. The afterpulsing is considerably decreased, which in return allows for higher signal sampling rates than in conventional gating schemes. This progress could bring forward in particular the photon counting OTDR (optical time domain reflectometer), which is used to monitor fiber links and networks. Besides the established classical telecommunication, using laser power of the order of milliwatts, quantum communication, using single photons to transfer information, could become an important part of daily communication. Here the integration of quantum cryptography systems into the existing fiber infrastructure is a crucial point. After thorough investigation of crucial fiber properties (presented in the last report), we demonstrate that the coexistence of classical telecommunication signals and single photon pulses and their subsequent efficient separation is feasable.
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Références bases de données
(Anglais)
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Swiss Database: COST-DB of the State Secretariat for Education and Research Hallwylstrasse 4 CH-3003 Berne, Switzerland Tel. +41 31 322 74 82 Swiss Project-Number: C06.0058
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