The Experts below are selected from a list of 162 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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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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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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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.
Helmut Ritsch - One of the best experts on this subject based on the ideXlab platform.
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Quantum noise in Raman lasers: Effects of Pump bandwidth and super- and sub-Poissonian Pumping.
Physical Review A, 1993Co-Authors: Helmut Ritsch, M. A. M. MarteAbstract:We investigate the influence of Pump bandwidth and Pump intensity noise on the quantum-noise properties of lasers based on a Raman atomic-gain medium, which recently have been predicted to emit narrow-bandwidth, sub-shot-noise light. We show that, using finite-bandwidth Pump light, the predicted limit to the laser bandwidth can still be well below the value given by the Shawlow-Townes formula and much smaller than the input bandwidth. The laser intensity noise is shown to be relatively insensitive to input phase noise as long as the Rabi frequency on the lasing transition is large compared to the bandwidth. On the other hand, even small amounts of Pump amplitude noise tend to increase strongly the laser spectral bandwidth, especially in the high-intensity limit. Including Dynamic Pump-noise reduction through multilevel atomic cycling in our model leads to a Mandel Q parameter value even below Q=-1/2, together with a significant enhancement of the output intensity-noise squeezing.
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Quantum Noise Reduction in Lasers by Dynamic Pump Noise Suppression
Quantum Measurements in Optics, 1992Co-Authors: Helmut Ritsch, P. ZollerAbstract:The standard theories for a single mode laser predict that far above threshold the laser generates a coherent state (with a phase randomly varying in time). Hence the counting statistics for the output photons is Poissonian and the intensity fluctuation spectrum is shot noise limited (this defines the so-called standard quantum limit (SQL)). Recently there have been several suggestions for developing a laser which produces states with reduced quantum fluctuations. Examples are a laser with sub-Poissonian Pump 1–4 (Pumping with amplitude squeezed light or a sequence of regularly spaced short Pump pulses) or a laser with an intracavity nonlinear absorbers5–8. In this work we identify a new mechanism of a dynamcial Pump noise suppression in multilevel laser systems which leads (at least in principle) to a complete reduction of the low frequency intensity noise9.
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Dynamic quantum noise reduction in multilevel laser systems
1992Co-Authors: Helmut Ritsch, M. A. M. Marte, P. ZollerAbstract:We show that the nonlinear Dynamics of the active atoms in conventionally Pumped multilevel laser systems can lead to output intensity fluctuations significantly below the shot noise level1,2 (see also Refs, 3-5). Our calculations are based on the standard model of the laser which assumes a large number of atoms resonantly coupled to a single lasing mode. We identify the multiple recycling of the active electron from the lower lasing level to the upper level through Pumping as the key process leading to this Dynamic Pump noise reduction. It is required that (i) the Pump rates be comparable to the decay rates of the atom, and (ii) we have a closed rePumping cycle, and a constant number of atoms. We find that the results are closely related to recent calculations based on the assumption of an external regular Pump6 (for noise reduction in semiconductor lasers, see Ref. 7).
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Sub-Poissonian laser light by Dynamic Pump-noise suppression
Physical Review A, 1991Co-Authors: Helmut Ritsch, C.w. Gardiner, Peter Zoller, Daniel F. WallsAbstract:We identify a mechanism of Dynamical Pump-noise suppression in lasers. It is based on the recycling of the active laser electron from the lower to the upper laser level by a sequence of incoherent step processes. Although each of these steps corresponds to a Poisson process, i.e., is stochastic, the combination of many incoherent steps leads to a regular (deterministic) recycling of the laser electron and, correspondingly, a Pump-noise suppression in the laser. The mechanism predicts sub-Poissonian laser output and intensity fluctuations beyond the shot-noise limit for incoherently Pumped systems. © 1991 The American Physical Society.
Daniel F. Walls - One of the best experts on this subject based on the ideXlab platform.
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Sub-Poissonian laser light by Dynamic Pump-noise suppression
Physical Review A, 1991Co-Authors: Helmut Ritsch, C.w. Gardiner, Peter Zoller, Daniel F. WallsAbstract:We identify a mechanism of Dynamical Pump-noise suppression in lasers. It is based on the recycling of the active laser electron from the lower to the upper laser level by a sequence of incoherent step processes. Although each of these steps corresponds to a Poisson process, i.e., is stochastic, the combination of many incoherent steps leads to a regular (deterministic) recycling of the laser electron and, correspondingly, a Pump-noise suppression in the laser. The mechanism predicts sub-Poissonian laser output and intensity fluctuations beyond the shot-noise limit for incoherently Pumped systems. © 1991 The American Physical Society.
P. Zoller - One of the best experts on this subject based on the ideXlab platform.
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Quantum Noise Reduction in Lasers by Dynamic Pump Noise Suppression
Quantum Measurements in Optics, 1992Co-Authors: Helmut Ritsch, P. ZollerAbstract:The standard theories for a single mode laser predict that far above threshold the laser generates a coherent state (with a phase randomly varying in time). Hence the counting statistics for the output photons is Poissonian and the intensity fluctuation spectrum is shot noise limited (this defines the so-called standard quantum limit (SQL)). Recently there have been several suggestions for developing a laser which produces states with reduced quantum fluctuations. Examples are a laser with sub-Poissonian Pump 1–4 (Pumping with amplitude squeezed light or a sequence of regularly spaced short Pump pulses) or a laser with an intracavity nonlinear absorbers5–8. In this work we identify a new mechanism of a dynamcial Pump noise suppression in multilevel laser systems which leads (at least in principle) to a complete reduction of the low frequency intensity noise9.
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Dynamic quantum noise reduction in multilevel laser systems
1992Co-Authors: Helmut Ritsch, M. A. M. Marte, P. ZollerAbstract:We show that the nonlinear Dynamics of the active atoms in conventionally Pumped multilevel laser systems can lead to output intensity fluctuations significantly below the shot noise level1,2 (see also Refs, 3-5). Our calculations are based on the standard model of the laser which assumes a large number of atoms resonantly coupled to a single lasing mode. We identify the multiple recycling of the active electron from the lower lasing level to the upper level through Pumping as the key process leading to this Dynamic Pump noise reduction. It is required that (i) the Pump rates be comparable to the decay rates of the atom, and (ii) we have a closed rePumping cycle, and a constant number of atoms. We find that the results are closely related to recent calculations based on the assumption of an external regular Pump6 (for noise reduction in semiconductor lasers, see Ref. 7).
Peter Zoller - One of the best experts on this subject based on the ideXlab platform.
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Sub-Poissonian laser light by Dynamic Pump-noise suppression
Physical Review A, 1991Co-Authors: Helmut Ritsch, C.w. Gardiner, Peter Zoller, Daniel F. WallsAbstract:We identify a mechanism of Dynamical Pump-noise suppression in lasers. It is based on the recycling of the active laser electron from the lower to the upper laser level by a sequence of incoherent step processes. Although each of these steps corresponds to a Poisson process, i.e., is stochastic, the combination of many incoherent steps leads to a regular (deterministic) recycling of the laser electron and, correspondingly, a Pump-noise suppression in the laser. The mechanism predicts sub-Poissonian laser output and intensity fluctuations beyond the shot-noise limit for incoherently Pumped systems. © 1991 The American Physical Society.
