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ABSTRACT: We present experimental results on transmission of 20 channels over 238 km long link composed of two spans (100 and 138 km) of non-zero dispersion shifted fibre. Transmission is based on distributed Raman amplification. Both spans are counter-directionally pumped by time-division-multiplexed four wavelengths optical units. Five of the 20 channels are 10 GB Ethernet signals (10 GE). Error-free transmission has been checked with 10 GE bit error ratio tester. Experimental results are extended by numerical simulations.
IET Optoelectronics 05/2010; · 1.03 Impact Factor
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ABSTRACT: This paper introduces the Czech National Research and Educational Network called CESNET2 and especially experimental facility. The paper also addresses a necessity of full access to the physical layer in experimental networking. Furthermore it summarizes research and experimental achievements and resources available for experimentation and formulates suggestions for the future international cooperation.
Testbeds and Research Infrastructures for the Development of Networks & Communities and Workshops, 2009. TridentCom 2009. 5th International Conference on; 05/2009
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ABSTRACT: Experimental and theoretical results of all-optical gain-clamping of wide-band TDM-pumped Raman fiber amplifier consisting of 13 km of DCF counter-directionally pumped by 4 wavelengths optical unit are presented.
Optical Fiber Communication - incudes post deadline papers, 2009. OFC 2009. Conference on; 04/2009
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ABSTRACT: We present experimental results on multi-wavelength conversion of one-to-six 10 Gb/s NRZ signals (10 Gigabit Ethernet, 10 GE) and one-to two 40 GHz RZ signals using a hybrid integrated SOA-MZI. The newly generated 10 GE signals were transmitted over 55 km of nonzero dispersion shifted fibre and the transmission quality tested by Ethernet bit error ratio tester.
Transparent Optical Networks, 2008. ICTON 2008. 10th Anniversary International Conference on; 07/2008
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ABSTRACT: This contribution deals with experimental investigation of usability of untraditional all-optical chromatic dispersion elements. Results are compared with traditional dispersion compensating fibres; emphasis was also given to tuneability and broadband characteristics of elements.
Optical Fiber Communication and Optoelectronics Conference, 2007 Asia; 11/2007
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ABSTRACT: We present experimental and theoretical results on transmission of ten 10 GE channels over 383 km long fibre link composed of 133 km non-zero dispersion shifted (NZDSF) and 150 km plus 100 km of standard single mode fibre (SSMF) based on distributed Raman amplification in the 3 fibre spans. Susceptibility of the transmission to channel addition/removal has been investigated by replacing 8 of the 10 GE XFP transceivers with signals from ILX-7900 WDM tester that were square-wave modulated at 500 Hz with 50% duty cycle.
Transparent Optical Networks, 2007. ICTON '07. 9th International Conference on; 08/2007
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ABSTRACT: In this contribution we compare experimental results based on application of different all-optical chromatic dispersion (CD) compensation techniques including tuneable ones. As fixed CD compensators, we used both channelized and broadband fibre Bragg gratings (FBG). Results obtained by application of thermally tuneable channelized FBGs and Gires-Tournois etalons (GTE) are also compared. In our experimental setup eight 10 Gigabit Ethernet (10 GE) channels were transmitted over 225 km of standard single mode fibre (SSMF) with no inline amplification. Signals were combined in multiplexer, amplified in a standard C-band erbium-doped fibre amplifier (EDFA) and launched in the SSMF fibre. At the receiver side, signals were first amplified in a low noise EDFA, CD was compensated by one of the elements and de-multiplexed. Partial CD pre- compensation was also tested.
Transparent Optical Networks, 2007. ICTON '07. 9th International Conference on; 08/2007
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ABSTRACT: Experimental results on error-free bidirectional transmission of 8times10 Gigabit Ethernet channels over 210 km of standard single mode fibre are presented here. Inexpensive XENPAKs transceivers, conventional unidirectional 1530-1560 nm (C-band) erbium-doped fibre amplifiers and fibre Bragg grating dispersion compensating modules have been used. The results are very promising, especially for operators of national research and educational networks
IET Optoelectronics 05/2007; · 1.03 Impact Factor
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ABSTRACT: We present experimental and theoretical results on power transients in an all-optical gain-clamped second order pumped lumped Raman fiber amplifier. Channel addition/removal was simulated by transmitting 10 signals, light of eight lasers was square-wave modulated.
Optical Fiber Communication and the National Fiber Optic Engineers Conference, 2007. OFC/NFOEC 2007. Conference on; 04/2007
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ABSTRACT: In this paper, the effect of addition and/or dropping of wavelength-division-multiplexed channels in an all- optical gain-clamped (AOGC) second-order (SO) pumped lumped Raman fiber amplifier (LRFA) has been investigated experimentally and analyzed by numerical simulation. Channel addition/ removal was simulated by transmitting ten signals through a counter-directionally pumped LRFA consisting of a 16-km-long dispersion-compensating fiber. The light from eight lasers was square-wave modulated at 500 Hz; power transients of the surviving channels caused by cross-gain modulation of the LRFA were monitored at the output of the amplifier. All-optical feedback loop was implemented in the form of a ring laser. Gain-clamping properties of the SO-pumped LRFA are compared with those of the first-order pumped LRFA having the same ON/OFF Raman gain. Theoretical analysis of the AOGC LRFA was based on numerical solution of coupled propagation equations for the backward propagating pump, signals, and both forward and backward propagating spectral components of amplified spontaneous emission powers.
Journal of Lightwave Technology 04/2007; · 2.78 Impact Factor
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ABSTRACT: We present experimental results and numerical simulations of multi-wavelength conversion of 10 Gb/s NRZ signals based on 2-pumps four-wave mixing, 10 Gb/s and 40 Gb/s RZ signals derived from supercontinuum (SC) generated in highly nonlinear fibre (HNLF). High quality SC with bandwidth exceeding 50 nm was generated when the HNLF was pumped with 25 dBm average power. Sliced SC can be used as a source for all-optical multicasting
Transparent Optical Networks, 2006 International Conference on; 07/2006
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ABSTRACT: In this letter, we study spectral optical signal-to-noise ratio (OSNR) profile of a wide-band Raman fiber amplifier (RFA)with time-division-multiplexed (TDM) pumping. We derive a comprehensive large-signal numerical model which incorporates time variation effects and the downstream propagation of signals, upstream propagation of pumps, and downstream and upstream propagation of amplified spontaneous emission spectral components. We present results for a four-wavelength-pumped discrete RFA with TDM and continuous-wave pumping. Improvement in OSNR flatness of 0.9 dB due to TDM pumping is demonstrated.
IEEE Photonics Technology Letters 10/2005; · 2.19 Impact Factor
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ABSTRACT: The effect of lasing wavelength selection and optical feedback loop loss on the performance of an all-optical gain-clamped (AOGC) lumped Raman fibre amplifier (LRFA) is investigated both theoretically and experimentally. Suppression of surviving channel power fluctuations is selected as a criterion of the performance of the AOGC LRFA. A large-signal numerical model which incorporates time variation effects and the downstream propagation of signals, upstream propagation of pumps and downstream and upstream propagation of amplified spontaneous emission (ASE) spectral components has been used for the theoretical analysis. The LRFAs consist of 13 km of counter-directionally pumped dispersion compensating fibre (DCF). In the experiment, channel addition/removal is simulated by propagating optical power from two laser diodes through the AOGC LRFA. One of them is square-wave modulated at 500 Hz and the power fluctuations of the continuous wave signal of the other laser diode caused by cross-gain saturation effect in LRFAs are monitored.
IEE Proceedings - Optoelectronics 09/2005; · 0.71 Impact Factor
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Transparent Optical Networks, 2005, Proceedings of 2005 7th International Conference; 08/2005
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ABSTRACT: In this contribution we investigate, both theoretically and experimentally, the effect of lasing wavelength and optical feedback loop loss on the performance of all-optical gain-clamped (AOGC) lumped Raman fibre amplifier (LRFA). As a criterion of the AOGC LRFA, we selected a suppression of surviving channel power fluctuations. The LRFA used for the experiments and the numerical analysis consists of 13 km of counter directionally pumped dispersion compensating fibre.
Transparent Optical Networks, 2005, Proceedings of 2005 7th International Conference; 08/2005
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Optical Network Design and Modeling, 2005. Conference on; 02/2005
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ABSTRACT: The effect of addition and/or dropping of wavelength-multiplexed channels in a network comprising three concatenated lumped Raman fiber amplifiers (LRFAs) have been analyzed by numerical simulation and verified experimentally. The first LRFA in the cascade is gain clamped using a ring-laser configuration, and the lasing power propagates through the cascade. A large-signal numerical model that incorporates time variation effects and the downstream propagation of signal, upstream propagation of pumps, and downstream and upstream propagation of amplified spontaneous emission spectral components has been used for the theoretical analysis. The LRFAs consist of 16 km of dispersion-compensating fiber counterdirectionally pumped at 1455 nm by a Raman fiber laser. Channel addition/removal is simulated by propagating through the cascade of LRFAs optical power from two laser diodes. One of them is square-wave modulated at 500 Hz, and power fluctuations of the second continuous-wave signal caused by the cross-gain saturation effect in LRFAs are monitored.
Journal of Lightwave Technology 11/2004; · 2.78 Impact Factor
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ABSTRACT: Application of all-optical gain-clamped (AOGC) lumped Raman fiber amplifier (RFA) for protection of surviving channels in multiwavelength networks is investigated experimentally and theoretically. Channel addition-removal was simulated by transmitting signals of two lasers through a counterdirectionally pumped RFA consisting of 16 km of dispersion compensating fiber. Light of one of the lasers was square-wave modulated at 500 Hz; power fluctuations of the other laser caused by cross-gain modulation of the RFA were monitored at the output of the amplifier with a digital oscilloscope. An all-optical feedback loop was implemented in the form of a ring laser. Theoretical analysis of the AOGC lumped RFA is based on numerical solution of coupled propagation equations for forward and backward-propagating pumps, signals, and spectral components of amplified spontaneous emission powers.
IEEE Photonics Technology Letters 04/2004; · 2.19 Impact Factor
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ABSTRACT: Performance limits of 10Gbit/s transmission over standard single mode fibre (SMF) without the deployment of in-line erbium-doped fibre amplifiers (EDFA's) are evaluated by means of numerical simulation. The fibre system was modelled using the standard split-step Fourier algorithm for the solution of nonlinear Schrodinger equation. The effect of group velocity dispersion (GVD) compensation scheme, degree of GVD compensation of the SMF, input optical powers to SMF and to the dispersion compensating fibre (DCF) has been investigated with the aim to maximize the distance between transmitter and receiver. We have found that post-compensation scheme performs better than the pre-compensation scheme and that, by careful selection of input powers and degree of GVD compensation, it should be possible to keep the bit-error-ratio (BER) bellow 10<sup>-15</sup> for SMF length of 270 km.
Telecommunications, 2003. ConTEL 2003. Proceedings of the 7th International Conference on; 07/2003
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ABSTRACT: The paper refers about a possibility to check carrier lifetime distribution over the area of power (large-area) solar cells. The carrier lifetime in volume of the cell body can be evaluated using local irradiation of the surface of large-area solar cells with a laser diode (λ = 820 nm) from measured values of open circuit voltage V<sub>oc</sub>. The method can give information about recombination centres distribution in large-area solar cells. From V<sub>oc</sub> distribution, also position and extent of local defects can also be determined. Solar cell diagnostic methods can be used to investigate the influence of technology on characteristics of solar cells, with the aim of increasing efficiency and reliability of solar cells.
Electronics Technology: Integrated Management of Electronic Materials Production, 2003. 26th International Spring Seminar on; 06/2003
