The Experts below are selected from a list of 22014 Experts worldwide ranked by ideXlab platform
Nattapong Kitsuwan - One of the best experts on this subject based on the ideXlab platform.
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Mathematical Model for Dynamic Pump-Wavelength Selection Switch
2015Co-Authors: Nattapong Kitsuwan, Dwina Fitriyandini SiswantoAbstract:This paper presents a mathematical model based on dynamic Pump-Wavelength selection for an optical packet switch (OPS). In the OPS, multiple packets that carry the same Wavelength from different input ports could be addressed to the same output port at the same time slot. This condition is called Wavelength contention. Of those contended packets, only one is forwarded to the output fiber while the others are dropped. Parametric Wavelength conversion is used to convert the contended Wavelengths into available non-contending Wavelengths. The OPS based on the dynamic Pump-Wavelength selection scheme, where the Pump-Wavelengths are adjusted based on the requests in every time slot, uses a heuristic matching algorithm to minimize the number of packet losses. However, there is no guarantee that the heuristic algorithm outputs the optimum result. The mathematical model presented in this paper is used to confirm the performance of the heuristic matching algorithm for the DPS-based OPS. A simulation shows that the heuristic matching algorithm achieves the same performance as the optimum solution provided by the mathematical model.
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Median-Pump Wavelength assignment scheme for optical networks with parametric Wavelength conversion
Optical Switching and Networking, 2014Co-Authors: Nattapong Kitsuwan, Maesaporn Leelasetakul, Eiji OkiAbstract:This paper proposes a Wavelength assignment scheme for optical networks with parametric Wavelength conversion to minimize the number of Wavelength converters when the number of Wavelengths is given. Wavelength conversion is needed to reduce the number of Wavelengths required in the network, since the number of Wavelengths is limited. A parametric Wavelength converter (PWC) can be used to reduce the number of Wavelength converters because of its multiple Wavelengths conversion function. PWC uses the Pump Wavelength to define original and converted Wavelengths. The setting of the Pump Wavelength affects the converted Wavelengths. Thus, the number of transmission Wavelengths depends on the position of the Pump Wavelength. The proposed scheme is a heuristic scheme that considers the position of Pump Wavelength. An output Wavelength that sets the Pump Wavelength near to the middle of the transmission Wavelength band is selected. The proposed scheme designs each PWC to maximize the number of Wavelength conversions supported. Numerical results with our examined networks indicate up to 37% reduction in the total number of converters required, compared to a scheme that the position of Pump Wavelength is not considered. Moreover, the reduction is 42% reduction compared to an optical network with single channel Wavelength converters.
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Performance of dynamic Pump-Wavelength selection for optical packet switch with chained parametric Wavelength conversion
IEEE OSA Journal of Optical Communications and Networking, 2014Co-Authors: Nattapong KitsuwanAbstract:This paper proposes a scheme for Pump-Wavelength selection in an optical packet switch (OPS) with parametric Wavelength converters (PWCs). In this scheme, Pump Wavelengths can be dynamically changed in all time slots, and more than one PWC is allowed to convert a Wavelength in a chained manner. The objective of this scheme is to minimize the packet loss rates of the OPS. This scheme is called dynamic Pump-Wavelength selection with chained parametric Wavelength conversion (DPS-C). DPS-C selects the Pump Wavelength for each PWC so as to maximize the number of successful requests, which refer to packets that wish to be forwarded to their requested output fibers. A PWC, which has the advantage of multiple Wavelength conversion, uses a Pump Wavelength that can be flexibly chosen to define which Wavelengths can be converted from/to. The set of original and converted Wavelengths, where the Pump Wavelength is set in the middle of the two Wavelengths, is called the conversion pair. Each PWC supports several conversion pairs. The OPS allows each Wavelength to be converted using combinations of available conversion pairs, which are not used by any requests, from more than one PWC. A simulation shows that DPS-C outperforms the conventional scheme in terms of packet loss rates in both uniform and nonuniform traffic patterns.
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HPSR - Dynamic Pump-Wavelength selection for optical packet switch with recursive parametric Wavelength conversion
2012 IEEE 13th International Conference on High Performance Switching and Routing, 2012Co-Authors: Nattapong KitsuwanAbstract:This paper proposes a scheme for Pump Wavelengths selection in an optical packet switch (OPS) with parametric Wavelength converters (PWCs), where the Pump Wavelengths are dynamically changed for all time slots and more than one PWC are allowed to convert a Wavelength in a recursive manner. This scheme is called a dynamic Pump-Wavelength selection with recursive parametric Wavelength conversion (DPS-R). A PWC, which has an advantage of multiple Wavelength conversion, uses a Pump Wavelength that can be flexibly chosen to define which Wavelengths can be converted from/to, called Wavelength conversion pairs. The OPS allows each Wavelength to be converted using combination of available conversion pairs from more than one PWC. A conventional scheme, Pump Wavelengths are statically preassigned, so that the conversion pairs are fixed for all time slots. Requests may remain since the Pump Wavelengths are not able to be reconfigured. The available conversion pairs may not support those requests. DPS-R is used to select the Pump Wavelength for each PWC to maximize the number of Wavelength conversion pairs supported, in both recursive and non-recursive manners. Numerical results via simulation show that DPS-R outperforms the conventional scheme in term of packet loss rate.
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Hybrid Pump-Wavelength configuration for optical packet switch with parametric Wavelength converters
2011 1st International Symposium on Access Spaces (ISAS), 2011Co-Authors: Nattapong Kitsuwan, Jaruwan YatjaroenAbstract:This paper proposes an optical packet switch (OPS) with parametric Wavelength converters (PWCs) that combines the advantages of static Pump Wavelength assignment (SPA) switch and dynamic Pump Wavelength selection (DPS) switch to trade off the performance in terms of packet loss rate and processing time. Since SPA switch has faster processing time than DPS switch, while DPS switch achieves high performance in term of packet loss rate. The combination of those schemes is an alternative for a network manufacture to adjust the network switch suit on user requirements. Simulation in limited environment is done to show the performance of hybrid configuration between SPA and DPS switches. The results of proposed scheme are better than SPA switch but not up to DPS switch in term of packet loss rate, while worse than SPA switch but not worse than DPS switch in term of processing time. However, the replacing one of dynamic PWC with Static PWC could decrease much processing time but effects to packet loss rates just a little bit worse. The results provide the useful information for switch manufacture in order to design the switch in variety specifications, which are expected to satisfy the various user requirements.
S. Georgescu - One of the best experts on this subject based on the ideXlab platform.
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Pump Wavelengths for an Er:YAG green-emitting laser
2006Co-Authors: O. Toma, S. GeorgescuAbstract:Mathematical modelling is used to study laser emission in an Er(0.5 at.%):YAG active medium on the transition 4S 3/2 → 41 15/2 for various Pump Wavelengths. The emission regimes corresponding to each Pump Wavelength are investigated. For upconversion Pumping, we find an optimum Pump Wavelength and optimum conditions for lowering of the emission threshold.© (2006) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
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The influence of Pump Wavelength on Er:YAG Green-emitting laser characteristics
IEEE Journal of Quantum Electronics, 2006Co-Authors: O. Toma, S. GeorgescuAbstract:Mathematical modeling is used to study the influence of Pump Wavelength on the emission of an Er(0.5 at.%):YAG laser on the transition /sup 4/S/sub 3/2//spl rarr//sup 4/I/sub 15/2/ (561 nm). Three Pump Wavelengths (direct Pumping: 488 nm, upconversion Pumping: 800 and 810 nm) are investigated and the corresponding laser emission regimes are discussed. For upconversion Pumping, we find an optimum Pump Wavelength and optimum resonator losses for lowering of the continuous-wave emission threshold.
Euan Hendry - One of the best experts on this subject based on the ideXlab platform.
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Impact of Pump Wavelength on terahertz emission of a cavity-enhanced spintronic trilayer
Applied Physics Letters, 2019Co-Authors: Rosamund I. Herapath, Samuel M. Hornett, Tom Seifert, Gerhard Jakob, Mathias Kläui, Jacopo Bertolotti, Tobias Kampfrath, Euan HendryAbstract:We systematically study the Pump-Wavelength dependence of terahertz pulse generation in thin-film spintronic THz emitters composed of a ferromagnetic CoFeB layer between adjacent nonmagnetic W and Pt layers. We find that the efficiency of THz generation is essentially flat for excitation by 150 fs pulses with center Wavelengths ranging from 900 to 1500 nm, demonstrating that the spin current does not depend strongly on the Pump photon energy. We show that the inclusion of dielectric overlayers of TiO2 and SiO2, designed for a particular excitation Wavelength, can enhance the terahertz emission by a factor of up to two in field.
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Impact of Pump Wavelength on Terahertz Emission of a Cavity-Enhanced Spintronic Trilayer
2019 44th International Conference on Infrared Millimeter and Terahertz Waves (IRMMW-THz), 2019Co-Authors: Rosamund I. Herapath, Samuel M. Hornett, Tom Seifert, Gerhard Jakob, Mathias Kläui, Jacopo Bertolotti, Tobias Kampfrath, Euan HendryAbstract:We investigate the Pump-Wavelength dependence of the THz generation from a novel spintronic THz emitter. We also add a weak cavity which reduces the transmission of the PumpWavelength and enhances the THz emission by a factor of four in intensity at a target Wavelength.
Seongwoo Yoo - One of the best experts on this subject based on the ideXlab platform.
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Pump Wavelength Dependence of Photodarkening in Yb-Doped Fibers
Journal of Lightwave Technology, 2017Co-Authors: L. Zhang, Raghuraman Sidharthan, Nalla Venkatram, Handong Sun, Tianye Huang, Seongwoo YooAbstract:Photodarkening in Yb-doped fibers is known to be dependent of Yb population inversion. In addition to this dependence, we report that Pump Wavelength selection plays a significant role in photodarkening dynamics. It is found that 976 nm Pump source can lead to more severe photodarkening effects than 916 nm Pumping at the same inversion levels. This observation is consistent in Yb-doped fibers with various compositions. Our work reveals Pump Wavelength is another determinant factor of photodarkening besides the inversion level and emphasizes the importance of Pump Wavelength selection in high power Yb-doped fiber lasers and amplifiers.
Hyo-hoon Park - One of the best experts on this subject based on the ideXlab platform.
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New Pump Wavelength of 1540-nm band for long-Wavelength-band erbium-doped fiber amplifier (L-band EDFA)
IEEE Journal of Quantum Electronics, 2003Co-Authors: Bo-hun Choi, Hyo-hoon ParkAbstract:A long-Wavelength-band erbium-doped fiber amplifier (L-band EDFA) using a Pump Wavelength source of 1540-nm band has been extensively investigated from a small single channel input signal to high-power Wavelength division multiplexing (WDM) signals. The small-signal gain coefficient of 1545-nm Pumping among the 1540-nm band is 2.25 times higher compared to the conventional 1480-nm Pumping. This improvement in gain coefficient is not limited by the Pumping direction. The cause for this high coefficient is explained by analyzing forward- and backward-amplified spontaneous emission spectra. The gain spectra as a function of a Pump Wavelength suggest that a broadband Pump source as well as a single Wavelength Pump can be used as a 1540-nm-band Pump. In the experiment for high-power WDM signals, the power conversion efficiency for 256 WDM channel input is 48.5% with 1545-nm Pumping. This result shows more than 20% improvement compared with the previous highest value for the L-band EDFA. Finally, the 1545-nm bidirectionally Pumped EDFA is applied as a second stage amplifier in an in-line amplifier of an optical communication link with a 1480-nm Pumped first stage EDFA, in which the input power of the second-stage EDFA is +2.2 dBm. The power conversion efficiency yields a 38% improvement without noise figure degradation compared with the case of 1480-nm Pumping.
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Investigation of Pump Wavelength dependence of long-Wavelength-band erbium-doped fiber amplifier using 1530 nm-band Pump for WDM amplification
OFC 2001. Optical Fiber Communication Conference and Exhibit. Technical Digest Postconference Edition (IEEE Cat. 01CH37171), 2001Co-Authors: Bo-hun Choi, Hyo-hoon ParkAbstract:The 1530 nm band was investigated as a new Pump Wavelength band of long-Wavelength-band Er/sup 3+/-doped fiber amplifier and compared with the conventional 1480 nm band. The gain coefficients of 1530 nm band Pumping were two times greater than those of 1480 nm Pumping.
