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G.M.T. Beleffi,
D.M. Forin,
S. Di Bartolo, G. Incerti,
V. Carrozzo,
A. Andò,
A. Busacca,
A.L.J. Teixeira,
L. Costa,
A. Valenti,
S. Pompei
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ABSTRACT: In this paper, the authors present the latest results on a simple and low cost method to achieve a dynamic and flexible network monitoring. By placing several fiber Bragg gratings (FBG) along the passive optical gigabit Ethernet infrastructure (GePON), the proposed modified optical time domain reflectometer (OTDR) is able to monitor the entire system by simply tuning its working wavelength. Furthermore, the optical network terminals (ONT), at the end users premises, have been interconnected to the trunk via an innovative cable able to both carry the optical signal as well as the power supply.
Transparent Optical Networks (ICTON), 2010 12th International Conference on; 08/2010
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ABSTRACT: Communications and transmissions are two fundamental concepts that follow the human being from the beginning. Free Space Optics is only one of the several choices that we have today in the complex and mixed telecommunication environment (WiFi, WiMax, LTE, Fibre, Coax, GSM, UMTS, et alt). With its inherent carachteristics like ease of installation, fast ROI, low CAPEX, intrinsic security, broad band and with its wide applications range, from under sea to deep space, free space optics represents today a solution that all the telecom actors have to take into account. Especially now that 10/100 GEthernet technology is appearing at the horizon.
03/2010; , ISBN: 978-953-307-072-8
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P.S. Andre,
A.M. Rocha,
B. Neto,
A. Martins,
M. Facao,
J.L. Pinto,
A.L.J. Teixeira,
R.N. Nogueira,
M.J. Lima, G. Incerti,
D. Forin,
G.T. Beleffi
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ABSTRACT: In this work the high power propagation in tight bent fibers was studied. The signal losses and the temperature increase have been experimental measured for single mode optical fibers (SMF) as function of the bending diameter. These results were used to propose an approach to limit the bending diameter, as a function of the injected power, in order to maintain the operational condition bellow the safety limit.
AFRICON, 2009. AFRICON '09.; 10/2009
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ABSTRACT: In this paper, we investigate experimentally the impact of optical amplifiers, namely Erbium Doped Fiber Amplifiers (EDFA) on Optical Burst Switching (OBS) networks, operating at 2.5 Gb/s (typical bit rate for current passive optical networks - PON). Bursts with 2<sup>12</sup> - 1 and 2<sup>16</sup> - 1 pseudo random binary sequence (PRBS) were studied, with different idle times (from 2 mus to 80 mus). The use of traffic with variable idle time was assessed in order to evaluate the effect on the burst initial amplitude. We also analyzed the performance of the packet based system by measuring the Q factor at the receiver and concluded that the performance is not affected by the type of traffic (variable or fixed idle times).
Transparent Optical Networks, 2009. ICTON '09. 11th International Conference on; 08/2009
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ABSTRACT: We experimentally show how the virtual private large-area network service (VPLS) technique, a layer 2 service, can improve optical network performance in terms of quality of service (QoS), and how a VPLS network behaves when it adopts all-optical wavelength conversion (AOWC), a new optical process that will be introduced in future optical networks. The advantages of VPLS are based on the capability to generate logical reliable paths in each wavelength channel, permitting suitable partitioning of the bandwidth according to the user requirements. In particular, we show the advantages of VPLS in access networks based on passive optical networks, and we test QoS properties of VPLS paths when an AOWC process occurs both in the core and in the access networks. The experimental investigation is carried out in a wide-area, all-optical gigabit Ethernet testbed with an access section based on an Ethernet passive optical network. As far as the core segment is concerned, we chose a high-efficiency AOWC process based on four-wave mixing in dispersion-shifted fiber; conversely in the access segment we chose a cheaper AOWC process based on cross gain modulation in a semiconductor optical amplifier. The reported results show that gigabit Ethernet transmission, with the relative layer 2 techniques, is also well suitable for wide-area WDM architectures, and in particular it is able to guarantee end-to-end QoS for huge bandwidth services such as high-definition TV and also in the case of congestion, restoration, and wavelength conversion processes.
Journal of Optical Communications and Networking 08/2009; · 1.87 Impact Factor
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ABSTRACT: We experimentally investigate the network performance of a wide area gigabit Ethernet test bed in which we introduced the all-optical wavelength conversion (WC) process. Such a test bed is configured to implement a quality of service (QoS) control based on the virtual private local area network service (VPLS), a technique that, according to the reported results, is well suitable to implement forwarding process based on dedicated wavelengths. We show that the all-optical WC does not degrade the QoS properties of the VPLS and it can be used with very fast switching time.
IEEE Photonics Technology Letters 01/2009; · 2.19 Impact Factor
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A. M. Rocha,
B. Neto,
A. Martins, G. Incerti,
D. Forin,
G. Bellefi,
M. Facao,
J. L. Pinto,
A. L. J. Teixeira,
R. N. Nogueira,
M. J. Lima,
P. S. Andre
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ABSTRACT: In this work we investigate, experimentally, the effect of high power launching in bent fibers. The bending losses and the coating heating imposed by high power propagation were measured. A maximum temperature of 130 degrees C was achieved in fibers which were subject to a maximum bend diameter of 8 mm, for a propagated optical power of 2 W at 1550 nm.
Contel 2009: Proceedings of the 10th International Conference on Telecommunications. 01/2009;
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ABSTRACT: Conference code: 78364, Export Date: 18 September 2012, Source: Scopus, Art. No.: 5206341, Language of Original Document: English, Correspondence Address: Militello, M.; University of Palermo, Via delle Scienze 9, 90128, Palermo, Italy; email: militellomarco@alice.it, References: Lee, C.C., Kao, T.C., Chi, S., Simultaneous Optical Monitoring and Fiber Supervising for WDM Networks Using an OTDR Combined With Concatenated Fiber Gratings (2001) IEEE Photonics Technology Letters, 13 (9), pp. 1026-1028;
2009 10th International Conference on Telecommunications, ConTEL 2009, Zagreb; 01/2009
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ABSTRACT: In this paper, the authors present results based on a 2R (re-amplification and re-shaping) multiwavelength regeneration system, with wavelength conversion capabilities. In a counter propagation approach, the system is able to regenerate several end user data stream at the same time opening the way to efficient wavelength allocation, network congestion reduction and QoS enhancement in the wide area optical network segment. A short review on the state of the art will be presented too.
Transparent Optical Networks, 2008. ICTON 2008. 10th Anniversary International Conference on; 07/2008
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ABSTRACT: Summary form only given. In order to increase the performances of the today DWDM backbone networks the simultaneously elaboration of more channels is request. New optical regeneration multichannel systems, based on non linear effects, exploit the optical medium properties to perform frequency convert and noise signal compression. Four wave mixing (FWM), as non linear effect in standard silica fibres and photonic crystal fibres, can be advantageously used to implement these new devices.
Transparent Optical Networks, 2007. ICTON '07. 9th International Conference on; 08/2007
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ABSTRACT: A new approach to characterise geographical areas with a drought risk index (DRI) is suggested, by applying an artificial neural network (ANN) classifier to bioclimatic time series for which operational temporal units (OtUs) are defined. A climatic database, corresponding to a grid of 8 km x 8 km cells covering the Italian peninsula, was considered. Each cell is described by the time series of seven variables recorded from 1989 to 2000. Sixteen cells were selected according to land cover homogeneity and completeness of the time series data. The periodic components of the time series were calculated by means of the fast Fourier transform (FFT) method. Temporal units corresponding to the period of the sinusoidal functions most related to the data were used as OtUs. The ANN for each OtU calculates a DRI value ranging between -1 and 1. The value is interpretable as the proximity of the OtUs to one of two situations corresponding to minimum and maximum drought risk, respectively. The former set (DRI = -1) is represented by an ideal OtU with minimum values of temperatures and evapo-transpiration, and maximum values of rainfall, normalised difference vegetation index (NDVI) and soil water content. The second set (DRI = 1) is represented by the reciprocal OtU to the former one. The classification of the cells based on DRI time profiles showed that, at the scale used in this work, DRI has no dependence on land cover class, but is related to the location of the cells. The methodology was integrated with GIS (geographic information system) software, and used to show the geographic pattern of DRI in a given area at different periods.
International Journal of Bioclimatology Biometeorology 04/2007; 51(4):253-63. · 2.25 Impact Factor
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ABSTRACT: 1 — In this paper, the transience of optical amplifiers (Raman and EDFA) at 10 Gbit/s burst transmission is assessed. For a set of two saturated EDFA over 50 km of standard single mode fiber (SSMF), the transience was clearly observable in the packet envelope but almost negligible for Raman amplifiers. Quantitative results were also obtained for Raman amplification over two spans 29425 m and 28816 m of SSMF. The results pointed out that Raman amplification is more suitable for operating in bursty traffic than EDFA.
