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International Journal of Computer Science and Network (IJCSN) Volume 1, Issue 1, February 2012 www.ijcsn.org ISSN 2277-5420 High Performance Efficiency of Distributed Optical Fiber Raman Amplifiers for Different Pumping Configurations in Schemes Different Fiber Cable Schemes 1 Abd El–Naser A. Mohamed, 2Ahmed Nabih Zaki Rashed, 3Mahmoud M. A. Eid 1,2,3 Electronics and Electrical Communication Engineering Department Faculty of Electronic Engineering, Menouf 32951, Menoufia University, EGYPT Abstract for the much slower electrical processing to occur had to Fiber Raman amplifiers (FRAs) are attractive for ultra wide be built into the system. In order to overcome the dense wavelength division multiplexing (UW-DWDM) limitations imposed by electrical regeneration, a means of transmission systems due to their advantages of broad optical amplification was sought. Two competing amplification bandwidth and flexible central wavelength. With technologies emerged: the first was erbium-doped fiber recent developments of optical pump sources with high power near 1.4 µm wavelength and highly nonlinear fiber having a amplifiers (EDFA) [2, 3] and the second Raman peak effective Raman gain coefficient more than ten times that amplification [4]. In the first deployed systems EDFA of conventional single mode fiber, distributed FRAs (DFRAs) emerged as the preferred approach. One reason was that are emerging as a practical optical amplifier technology, the optical pump powers required for Raman especially for opening new wavelength windows such as the amplification were significantly higher than that for short and ultra long wavelength bands. Optical pump powers EDFA, and the pump laser technology could not reliably required for Raman amplification were significantly higher than deliver the required powers. However, with the that for Erbium doped fiber amplifier (EDFA), and the pump improvement of pump laser technology Raman laser technology could not reliably deliver the required powers. amplification is now an important means of expanding However, with the improvement of pump laser technology Raman amplification is now an important means of expanding span transmission reach and capacity [5]. span transmission reach and capacity. In the present paper, we In a multiple wavelength telecom system it is have deeply investigated the proposed model for optical important that all signal wavelengths have similar optical distributed fiber Raman amplifiers in the transmission signal powers. The variation in the gain provided to different power and pump power within Raman amplification technique wavelengths after passing through an amplifier is referred in co-pumped, counter-pumped, and bi-directional pumping to as the gain flatness. If the signal at one wavelength is direction configurations through different types of fiber cable disproportionately amplified, as it passes through several media. The validity of this model was confirmed by using amplifiers, it will grow super linearly relative to the other experimental data and numerical simulations. channels reducing the gain to other channels [6]. The Keywords: Distributed fiber Raman amplifier, Signal power, system, however, will still be limited by the channel with Pumping power, Forward pumping, Different fiber media, the lowest gain. As a result, after each amplifier the gain Backward pumping, and Bidirectional pumping configuration. spectrum generally is flattened. One approach is to insert wavelength-dependent lossy elements, within the 1. Introduction amplifier, with the appropriate spectral profile. Raman The first fiber optical telecommunication systems amplification offers the ability to achieve this without emerged with the engineering of low loss optical fiber [1]. lossy elements. In Raman amplification a flat spectral Even though the complexity of the system has increased, profile can be obtained by using multiple pump the basic elements remain the same. They consist of an wavelengths [7, 8]. For a given fiber the location of the optical source, a means of modulating the source, the Raman gain is only dependent on the wavelength of the transmission medium (i.e., the optical fiber), and a pump, the magnitude of the gain is proportional to the detector at the output end of the fiber. Fiber loss is one pump power, and the shape of the gain curve is limitation to the transmission distance of this system. In independent of the pump wavelength. Therefore, if the early days of fiber-optic communications the loss of multiple pumps are used a flat spectral gain profile can be the fiber was compensated for in long spans by using obtained [9]. The required pump wavelengths and the gain electrical regenerators. As their name implies, these required at each wavelength can be predicted by summing devices detected the signal, converted it to an electrical the logarithmic gain profiles at the individual pump signal, and using a new laser transmitted a new version of wavelengths [10]. the signal. Electrical regenerators were expensive and also In the present study, we have deeply analyzed the limited the rate at which data could be transmitted as time signal power, pumping power, rate of change of signal, International Journal of Computer Science and Network (IJCSN) Volume 1, Issue 1, February 2012 www.ijcsn.org ISSN 2277-5420 pumping powers with respect to transmission distance both of the pump can be equal or different in the used under the variations of signal, pump powers and signal wavelength or the used amount of power, therefore in this and pump wavelengths for different fiber link media in case the following equation can be used to calculate the different pumping direction configurations (forward, pump power at point z [14]: backward, and bi-directional) over wide range of the operating parameters. PFB ( ) P (z) = (rf)PpoFexp−αLp z +(1−rf ) PpoBexp−αLp(L− z) [ ] (8) Where rf is the percentage of pump power launched in the 2. Modeling Analysis forward direction. If the values of PP are substituted in Signals fad with distance when they traveling through differential Eq. (2), and is integrated from z=0 to z=L for any type of media. As the optical signal moves along a the signal power in the forward and the backward SMF, it gets attenuated along the fiber. The signal power when it travels through the distance z without any pumping the result mathematical equation can be written amplification, PsWNA can be expressed as following: as mentioned in [13]: PsWNA (z ) = Pso exp (−α Ls z ) (1) g PS (z ) = Pso exp R P L − α z (9) Aeff po eff Ls Systems avoid this problem by amplifying signals along the way. So there is a need for using optical fiber where Pso and Ppo denotes to the input signal and pump amplifiers. The evolution of the input signal power (Ps) power respectively. This means that Ppo = PpoF in case of and the input pump power (Pp) propagating along the forward pump and Ppo=PpoB in case of backward pump, single mode optical fiber in watt; can be quantitatively and Leff, is the effective length in km, over which the described by different equations called propagation nonlinearities still holds or SRS occurs in the fiber and is equations. The rate of change of signal and pump power defined as [15]: with the distance z, can be expressed as mentioned in Leff = ( 1 − exp − α Lp z ) (10) [11]: α Lp dPp λ = −α Lp Pp ( z ) − s g Re ff Ps ( z ) Pp ( z ) (2) Recently, there have been many efforts to utilize fiber dz λp Raman amplifier (FRA) in long-distance, high capacity dPs λ WDM systems. This is mainly because FRA can improve = −α Ls Ps ( z ) + s g Re ff Ps ( z ) Pp ( z ) (3) dz λp the optical signal to noise ratio (OSNR) and reduce the Where λs and λp are the signal and pump wavelengths in impacts of fiber nonlinearities [16]. µm respectively, z is the distance in km from z=0 to z=L, αLs and αLp are the linear attenuation coefficient of the 3. Simulation Results and Analysis signal and pump power in the optical fiber in km-1 In the present study, the optical distributed Raman respectively, The linear attenuation, αL can be expressed amplifiers have been modeled and have been as: parametrically investigated, based on the coupled α L = α /4.343 (4) differential equations of first order, and also based on the Where α is the attenuation coefficient in dB/km. gReff is set of the assumed of affecting operating parameters on the Raman gain efficiency in W-1km-1 of the fiber cable the system model. In fact, the employed software length, L in km, which is a critical design issue and is computed the variables under the following operating given by the following equation: parameters as shown in Table 1. gR Table1. Vvalues of operating parameters in proposed model. g Reff = (5) A eff × 10 − 18 Operating Symbol Value Where gR is the maximum Raman gain in km W-1, Aeff the parameter effective area of the fiber cable used in the amplification Operating in µm2. Equation (1) can be solved when both sides of the signal λs 1.45 ≤ λs, µm ≤ 1.65 equation are integrated. When using forward pumping, the wavelength pump power can be expressed as the following expression Operating [12]: pump λp 1.40 ≤ λp, µm ≤ 1.44 PPF (z ) = P poF exp (− α Lp z ) (6) wavelength Where PPoF , is the input pump power in the forward Input signal Pso 0.002 ≤ Pso, W ≤ 0.02 direction in watt at z=0. power In the backward pumping the pump power is given by Input pump [13]: power Ppo 0.165 ≤ Ppo, W ≤ 0.365 PPB (z ) = PpoB exp [− α Lp (L − z )] (7) Percentage of Where PPoB , is the input pump power in the backward rf 0.5 power direction in watt at z=L. In the case of bi-directional pump International Journal of Computer Science and Network (IJCSN) Volume 1, Issue 1, February 2012 www.ijcsn.org ISSN 2277-5420 launched in parameters as displayed in Figs. (5-11), these figures forward clarify the following results: direction a- Without any amplification: with increasing Attenuation distance, z, the output signal power decreases of the signal exponentially. power in αS 0.25 dB/km b- In case of forward direction: silica-doped 1) For certain value of initial pumping power: fiber i. Initial pumping power = 0.165 mW, for Attenuation of the pump distance z ≤ 2 km, the output signal power power in αP 0.3 dB/km increases exponentially, and for z ≥ 2 km, the silica-doped output signal power decreases exponentially. fiber ii. Initial pumping power = 0.265 mW, for Types of fiber cable Truewave LEAF distance z ≤ 8 km, the output signal power SMF-28 Unit media reach (NZ- (NDSF) increases exponentially, and for z ≥ 8 km, the fiber DSF) output signal power decreases exponentially. Effective Aeff 55 72 84.95 (µm) 2 iii. Initial pumping power = 0.365 mW, for Area distance z ≤ 13 km, the output signal power Raman Gain (W.km)- increases exponentially, and for z ≥ 13 km, gReff 0.6 0.45 0.38 1 the output signal power decreases Efficiency exponentially. The following points of discussion will cover all operating 2) For certain value of distance z: design parameters of multiplexing/demultiplexing based i. With increasing the initial pumping power, optical distributed Raman amplifier device, such as, input the output signal power also will increase. signal power, input pumping power, operating signal ii. With increasing the initial signal power, the wavelength, operating pump wavelength, and different output signal power also will increase. fiber link media. Then based on the basic model analysis 3) After using different media of optical fiber cable, and the set of the series of the following figures are shown it is indicated that the true wave reach fiber below, the following facts can be obtained: presented the best results. c- In case of backward direction: 3. 1. Variations of the output pumping power, Pp The results are the same as in case of forward Variation of the output pumping power, Pp is direction. investigated against variations of the controlling set of d- In case of bi-directional: parameters as displayed in Figs. (1-4), these figures 1) For certain value of initial pumping power: clarify the following results: i. Initial pumping power = 0.165 W, for a- In case of forward direction: distance z ≤ 1 km, the output signal power i. As distance z increases, the output increases exponentially, for 1 ≤ z, km ≤50 the pumping power decreases exponentially. output signal power decreases exponentially, ii. For certain value of distance z, with and for z ≥ 50 km, the output signal power increasing the initial pumping power, the increases exponentially again. output pumping power also will increase. ii. Initial pumping power = 0.265 W, for b- In case of backward direction: distance z ≤ 8 km, the output signal power i. As distance z increases, the output increases exponentially, for 8 ≤ z, km ≤49 the pumping power increases exponentially. output signal power decreases exponentially, ii. For certain value of distance z, with and for z ≥ 49 km, the output signal power increasing the initial pumping power, the increases exponentially again. output pumping power also will increase. iii. Initial pumping power = 0.365 W, for c- In case of bi-directional: distance z ≤ 13 km, the output signal power i. For z ≤ 50 km, the output pumping power increases exponentially, for 13 ≤ z, km ≤ 48 decreases exponentially, and for z ≥ 50 the output signal power decreases km, PpFB increases exponentially. exponentially, and for z ≥ 48 km, the output ii. For certain value of distance z, with signal power increases exponentially again. increasing the initial pumping power, the 2) For certain value of distance z: output pumping power also will increase. i. With increasing the initial signal power, the 3. 2. Variations of the output signal power, Ps output signal power also will increase. Variation of the output signal power, Ps is ii. With increasing the initial pumping power, investigated against variations of the controlling set of the output signal power also will increase. International Journal of Computer Science and Network (IJCSN) Volume 1, Issue 1, February 2012 www.ijcsn.org ISSN 2277-5420 3) After using different media of optical fiber cable, it is indicated that the true wave reach fiber presented the best results. Fig. 1. Variations of pump power in different configurations against variations of distance at the assumed set of the operating parameters. Fig. 2. Variations of pump power in forward direction against variations of distance z at the assumed set of the operating parameters. International Journal of Computer Science and Network (IJCSN) Volume 1, Issue 1, February 2012 www.ijcsn.org ISSN 2277-5420 Fig. 3. Variations of pump power in backward direction against variations of distance z at the assumed set of the operating parameters. Fig. 4. Variations of pump power in bi-directional case against variations of distance z at the assumed set of the operating parameters. International Journal of Computer Science and Network (IJCSN) Volume 1, Issue 1, February 2012 www.ijcsn.org ISSN 2277-5420 Fig. 5. Variations of signal power in different configurations against variations of distance z at the assumed set of the operating parameters. . Fig. 6. Variations of signal power in forward direction against variations of distance z at the assumed set of the operating parameters. International Journal of Computer Science and Network (IJCSN) Volume 1, Issue 1, February 2012 www.ijcsn.org ISSN 2277-5420 Fig. 7. Variations of signal power in forward direction against variations of distance z at the assumed set of the operating parameters. Fig. 8. Variations of signal power in forward direction against variations of distance z at the assumed set of the operating parameters. International Journal of Computer Science and Network (IJCSN) Volume 1, Issue 1, February 2012 www.ijcsn.org ISSN 2277-5420 Fig. 9. Variations of signal power in bi-directional case against variations of distance z at the assumed set of the operating parameters. Fig. 10. Variations of signal power in case of bi-directional case against variations of distance z at the assumed set of the operating parameters. International Journal of Computer Science and Network (IJCSN) Volume 1, Issue 1, February 2012 www.ijcsn.org ISSN 2277-5420 Fig. 11. Variations of signal power in bi-directional case against variations of distance z at the assumed set of the operating parameters. Fig. 12. Variations of rate of change of pump power in different configurations against variations of distance z at the assumed set of the operating parameters. International Journal of Computer Science and Network (IJCSN) Volume 1, Issue 1, February 2012 www.ijcsn.org ISSN 2277-5420 Fig. 13. Variations of rate of change of pump power in forward direction against variations of distance z at the assumed set of the operating parameters. Fig. 14. Variations of rate of change of pump power in forward direction against variations of distance z at the assumed set of the operating parameters. International Journal of Computer Science and Network (IJCSN) Volume 1, Issue 1, February 2012 www.ijcsn.org ISSN 2277-5420 Fig. 15. Variations of rate of change of pump power in backward direction against variations of distance z at the assumed set of the operating parameters. Fig. 16. Variations of rate of change of pump power in bi-directional case against variations of distance z at the assumed set of the operating parameters. International Journal of Computer Science and Network (IJCSN) Volume 1, Issue 1, February 2012 www.ijcsn.org ISSN 2277-5420 Fig. 17. Variations of rate of change of pump power in bi-directional pumping case against variations of distance z at the assumed set of the operating parameters. Fig. 18. Variations of rate of change of signal power in different configurations against variations of distance z at the assumed set of the operating parameters. International Journal of Computer Science and Network (IJCSN) Volume 1, Issue 1, February 2012 www.ijcsn.org ISSN 2277-5420 Fig. 19. Variations of rate of change of signal power in forward direction against variations of distance z at the assumed set of the operating parameters. Fig. 20. Variations of rate of change of signal power in forward direction against variations of distance z at the assumed set of the operating parameters. International Journal of Computer Science and Network (IJCSN) Volume 1, Issue 1, February 2012 www.ijcsn.org ISSN 2277-5420 Fig. 21. Variations of rate of change of signal power in forward direction against variations of distance z at the assumed set of the operating parameters. Fig. 22. Variations of rate of change of signal power in forward direction against variations of distance z at the assumed set of the operating parameters. International Journal of Computer Science and Network (IJCSN) Volume 1, Issue 1, February 2012 www.ijcsn.org ISSN 2277-5420 Fig. 23. Variations of rate of change of signal power in forward direction against variations of distance z at the assumed set of the operating parameters. Fig. 24. Variations of rate of change of signal power in backward direction against variations of distance z at the assumed set of the operating parameters. International Journal of Computer Science and Network (IJCSN) Volume 1, Issue 1, February 2012 www.ijcsn.org ISSN 2277-5420 Fig. 25. Variations of rate of change of signal power in backward direction against variations of distance z at the assumed set of the operating parameters. Fig. 26. Variations of rate of change of signal power in backward direction against variations of distance z at the assumed set of the operating parameters. International Journal of Computer Science and Network (IJCSN) Volume 1, Issue 1, February 2012 www.ijcsn.org ISSN 2277-5420 Fig. 27. Variations of rate of change of signal power in bi-directional case against variations of distance z at the assumed set of the operating parameters. Fig. 28. Variations of rate of change of signal power in bi-directional pumping case against variations of distance z at the assumed set of the operating parameters. International Journal of Computer Science and Network (IJCSN) Volume 1, Issue 1, February 2012 www.ijcsn.org ISSN 2277-5420 Fig. 29. Variations of rate of change of signal power in bi-directional pumping case against variations of distance z at the assumed set of the operating parameters. Fig. 30. Variations of rate of change of signal power in bi-directional pumping case against variations of distance z at the assumed set of the operating parameters. International Journal of Computer Science and Network (IJCSN) Volume 1, Issue 1, February 2012 www.ijcsn.org ISSN 2277-5420 Fig. 31. Variations of rate of change of signal power in bi-directional pumping case against variations of distance z at the assumed set of the operating parameters. 3. 3. Variations of rate of change of pump power, Variation of the rate of change of signal power in dPp/dz different configurations; dPs/dz is investigated against Variation of the rate of change of pump power in variations of the controlling set of parameters as displayed different configurations; dPp/dz is investigated against in Figs. (18-31), these figures clarify the following results: variations of the controlling set of parameters as displayed a- In case of forward direction: in Figs. (12-17). these figures clarify the following results: 1) For certain value of initial pumping power: a- In case of forward direction: i. Initial pumping power = 0.165 W, for 0 ≤ z, i. As distance z increases, dPpF/dz decreases km ≤ 3, dPsF/dz decreases linearly, for 3 ≤ z, exponentially. km ≤ 18, dPsF/dz increases exponentially, and ii. For certain value of distance z, with for z ≥ 18 km, dPsF/dz decreases increasing the initial pumping power, exponentially. dPpF/dz also will increase. ii. Initial pumping power = 0.265 W, for 0 ≤ z, iii. For certain value of distance z, with km ≤ 10, dPsF/dz decreases linearly, for 10 ≤ increasing the initial signal power, dPpF/dz z, km ≤ 24, dPsF/dz increases exponentially, also will increase for z ≥ 24 km, dPsF/dz decreases b- In case of backward direction: exponentially. i. As distance z increases, dPpB/dz increases iii. Initial pumping power = 0.365 W, for 0 ≤ z, exponentially. km ≤ 14, dPsF/dz decreases linearly, for 14 ≤ ii. For certain value of distance z, with z, km ≤ 29, dPsF/dz increases exponentially, increasing the initial pumping power, for z ≥ 29 km, dPsF/dz decreases dPpB/dz also will increase. exponentially. c- In case of bi-directional: 2) For any value of initial signal power: for 0 ≤ z, i. For z ≤ 50 km, dPpFB/dz decreases km ≤ 3, dPsF/dz decreases linearly, for 3 ≤ z, km exponentially, and for z ≥ 50km, dPpFB/dz ≤ 18, dPsF/dz increases exponentially, and for z ≥ increases exponentially. 18 km, dPsF/dz decreases exponentially. ii. For certain value of distance z, with 3) For certain value of distance, z: increasing the initial pumping power, i. With increasing the initial signal power, dPpFB/dz also will increase. dPpF/dz also will increase. iii. For certain value of distance z, with ii. With increasing the initial pumping power, increasing the initial signal power, dPpF/dz also will increase. dPpFB/dz also will increase. 4) For certain value operating signal wavelength, λs: 3. 4. Variations of rate of change of signal power, i. λs = 1.45 µm, for 0 ≤ z, km ≤ 2, dPsF/dz dPs/dz decreases linearly, for 2 ≤ z, km ≤ 17, International Journal of Computer Science and Network (IJCSN) Volume 1, Issue 1, February 2012 www.ijcsn.org ISSN 2277-5420 dPsF/dz increases exponentially, and for z ≥ and for z ≥ 11 km, dPsFB/dz decreases 17 km, dPsF/dz decreases exponentially. exponentially. ii. λs = 1.55 µm, for 0 ≤ z, km ≤ 3, dPsF/dz ii. Initial pumping power = 0.265 W, for 0 ≤ z, decreases linearly, for 3 ≤ z, km ≤ 18, km ≤ 10, dPsFB/dz decreases linearly, for 10 ≤ dPsF/dz increases exponentially, and for z ≥ z, km ≤ 18, dPsFB/dz increases exponentially, 18 km, dPsF/dz decreases exponentially. for z ≥ 18 km, dPsFB/dz decreases iii. λs = 1.65 µm for 0 ≤ z, km ≤ 4, dPsF/dz exponentially. decreases linearly, for 4 ≤ z, km ≤ 19, iii. Initial pumping power = 0.365 W, for 0 ≤ z, dPsF/dz increases exponentially, and for z ≥ km ≤ 14, dPsFB/dz decreases linearly, for 14 ≤ 19 km, dPsF/dz decreases exponentially. z, km ≤ 22, dPsFB/dz increases exponentially, 5) At the beginning with increasing the operating for z ≥ 22 km, dPsFB/dz decreases signal wavelength, λs dPsF/dz also will increase, exponentially. after that dPsF/dz decreases with increasing the 2) For any value of initial signal power: for 0 ≤ z, operating signal wavelength, λs. km ≤ 3, dPsFB/dz decreases linearly, for 3 ≤ z, km 6) For certain value operating pump wavelength, λp: ≤ 11, dPsFB/dz increases exponentially, and for z i. λp = 1.40 µm, for 0 ≤ z, km ≤ 3, dPsF/dz ≥ 11 km, dPsFB/dz decreases exponentially. decreases linearly, for 3 ≤ z, km ≤ 18, 3) For certain value of distance, z: dPsF/dz increases exponentially, and for z ≥ i. With increasing the initial signal power, 18 km, dPsF/dz decreases exponentially. dPsFB/dz also will increase. ii. λp = 1.42 µm, for 0 ≤ z, km ≤ 2, dPsF/dz ii. With increasing the initial pumping power, decreases linearly, for 2 ≤ z, km ≤ 17, dPsFB/dz also will increase. dPsF/dz increases exponentially, and for z ≥ 4) For certain value operating signal wavelength, λs: 17 km, dPsF/dz decreases exponentially. i. λs = 1.45 µm, for 0 ≤ z, km ≤ 2, dPsFB/dz iii. λp = 1.44 µm for 0 ≤ z, km ≤ 1, dPsF/dz decreases linearly, for 2 ≤ z, km ≤ 10, decreases linearly, for 1 ≤ z, km ≤ 16, dPsFB/dz increases exponentially, and for z ≥ dPsF/dz increases exponentially, and for z ≥ 10 km, dPsFB/dz decreases exponentially. 16 km, dPsF/dz decreases exponentially. ii. λs = 1.55 µm, for 0 ≤ z, km ≤ 3, dPsFB/dz 7) After using different media of optical fiber cable, decreases linearly, for 3 ≤ z, km ≤ 11, it is indicated that the true wave reach fiber dPsFB/dz increases exponentially, and for z ≥ presented the best results. 11 km, dPsFB/dz decreases exponentially. b- In case of backward direction: iii. λs = 1.65 µm for 0 ≤ z, km ≤ 4, dPsFB/dz 1) For certain value of initial pumping power: decreases linearly, for 4 ≤ z, km ≤ 12, i. Initial pumping power = 0.165 mW, for dPsFB/dz increases exponentially, and for z ≥ distance z ≤ 2 km, dPsB/dz increases 12 km, dPsFB/dz decreases exponentially. exponentially, and for z ≥ 2 km, dPsB/dz 5) At the beginning with increasing the operating decreases exponentially. signal wavelength, λs dPsFB/dz also will increase, ii. Initial pumping power = 0.265 mW, for after that dPsFB/dz decreases with increasing the distance z ≤ 8 km, dPsB/dz increases operating signal wavelength, λs. exponentially, and for z ≥ 8 km, dPsB/dz 6) For certain value operating pump wavelength, λp: decreases exponentially. i. λp = 1.40 µm, for 0 ≤ z, km ≤ 3, dPsFB/dz iii. Initial pumping power = 0.365 mW, for decreases linearly, for 3 ≤ z, km ≤ 11, distance z ≤ 13 km, dPsB/dz increases dPsFB/dz increases exponentially, and for z ≥ exponentially, and for z ≥ 13 km, dPsB/dz 11 km, dPsFB/dz decreases exponentially. decreases exponentially. ii. λp = 1.42 µm, for 0 ≤ z, km ≤ 2, dPsFB/dz 2) For certain value of distance z: decreases linearly, for 2 ≤ z, km ≤ 11, iii. With increasing the initial pumping power, dPsFB/dz increases exponentially, and for z ≥ dPsB/dz also will increase. 11 km, dPsFB/dz decreases exponentially. iv. With increasing the initial signal power, iii. λp = 1.44 µm for 0 ≤ z, km ≤ 1, dPsFB/dz dPsB/dz also will increase. decreases linearly, for 1 ≤ z, km ≤ 11, 3) After using different media of optical fiber cable, dPsFB/dz increases exponentially, and for z ≥ it is indicated that the true wave reach fiber 11 km, dPsFB/dz decreases exponentially. presented the best results. After using different media of optical fiber c- In case of bi-directional: cable, it is indicated that the true wave reach 1) For certain value of initial pumping power: fiber presented the best results. i. Initial pumping power = 0.165 W, for 0 ≤ z, km ≤ 3, dPsFB/dz decreases linearly, for 3 ≤ z, 4. Conclusions km ≤ 11, dPsFB/dz increases exponentially, International Journal of Computer Science and Network (IJCSN) Volume 1, Issue 1, February 2012 www.ijcsn.org ISSN 2277-5420 In a summary, The points of discussion indicated all [8] S. Shahi, S. W. Harun, K. Dimyati, and H. Ahmad, the operating design parameters of "Brillouin Fiber Laser With Significantly Reduced Gain multiplexing/demultiplexing based distributed optical Medium Length Operating in L Band Region," Progress In fiber Raman amplifier device, such as input signal power, Electromagnetics Research Letters, Vol. 8, No. 3, pp. 143- 149, 2009. input pumping power, operating signal wavelength, [9] A. Banerjee, "New Approach to Design Digitally Tunable operating pump wavelength, and different fiber link Optical Fiber System for Wavelength Selective Switching media. Therefore we have deeply investigated Based Optical Networks," Progress In Electromagnetics multiplexing/demultiplexing based distributed optical Research Letters, Vol. 9, No. 2, pp. 93-100, 2009. fiber Raman amplifier over wide range of the affecting [10] Abd El-Naser A. Mohammed and Ahmed Nabih Zaki parameters. As well as we have taken into account signal Rashed, “Ultra Wide Band (UWB) of Optical Fiber Raman power, pumping power, and the rate of change of both Amplifiers in Advanced Optical Communication Networks,” signal power and pumping power along the transmission Journal of Media and Communication Studies (IJMCS), Vol. distance within the variety of operating signal wavelength, 1, No. 4, pp. 56-78, 2009. [11] S. Makoui, M. Savadi-Oskouei, A. Rostami, and Z. D. operation pumping wavelength, input signal power, input Koozehkanani, "Dispersion Flattened Optical Fiber Design for pumping power, different fiber link media, and finally Large Bandwidth and High Speed Optical Communications Raman gain efficiency for all pumping direction Using Optimization Technique," Progress In Electromagnetics configurations such as forward, backward, and bi- Research B, Vol. 13, No. 3, pp. 21-40, 2009. directional pumping. The effects of the verity of these [12] M. El Mashade, M. B. and M. N. Abdel Aleem, "Analysis parameters are mentioned in details in the previous of Ultra Short Pulse Propagation in Nonlinear Optical Fiber," section of the results and performance analysis. After Progress In Electromagnetics Research B, Vol. 12, No. 3, pp. using different media of optical fiber cable, it is indicated 219-241, 2009. [13] Abd El Naser A. Mohammed, Mohamed Metawe'e, Ahmed that the true wave reach fiber presented the best candidate Nabih Zaki Rashed, and Mahmoud M. A. Eid, “Distributed media for the highest signal transmission performance Optical Raman Amplifiers in Ultra High Speed Long Haul efficiency. Transmission Optical Fiber Telecommunication Networks,” International Journal of Computer and Network Security REFERENCES (IJCNS), Vol. 1, No.1, pp. 1-8, 2009. [1] Maan M. Shaker, Mahmood Sh. Majeed, and Raid W. [14] S. Raghuawansh, V. Guta, V. Denesh, and S. Talabattula, Daoud, “Functioning the Intelligent Programming to find “Bi-directional Optical Fiber Transmission Scheme Minimum Dispersion Wavelengths,” Wseas Transactions on Through Raman Amplification: Effect of Pump Depletion,” Communications, Vol. 8, No. 2, pp. 237-248, 2009. Journal of Indian Institute of Science, Vol. 5, No. 2, pp. [2] M. V. Raghavendra, and P. L. H. Vara Prasad, “Estimation 655-665, 2006. of Optical Link Length for Multi Haul Applications,” [15] C.J.S. de Matos, K.P. Hansen and J.R. Taylor, International Journal of Engineering Science and Technology, “Experimental Characterization of Raman Gain Efficiency Vol. 2, No. 6, pp. 1485-1491, 2010. of Holey Fiber,” Electronics Letters, Vol. 39, No.5, pp. [3] Abd El-Naser A. Mohammed, and Ahmed Nabih Zaki 424, Mar. 2003. Rashed, “Comparison Performance Evolution of Different [16] E. S. Son, J. H. Lee, and Y. C. Chung, “Statistics of Transmission Techniques With Bi-directional Distributed Polarization-Dependent Gain in Fiber Raman Amplifiers," Raman Gain Amplification Technique in High Capacity J. Lightwave Technol., Vol. 23, No.3, pp. 1219-1226, Mar. Optical Networks,” International Journal of Physical Sciences, 2005. Vol. 5, No. 5, pp. 484-495, 2010. [4] Ming-Jun Li, and Daniel A. Nolan, “Optical Transmission Fiber Design Evolution,” J. Lightwave Technol., Vol. 26, No. 9, pp. 1079-1092, 2008. [5] Abd El-Naser A. Mohammed, Gaber E. S. M. El-Abyad, Abd El-Fattah A. Saad, and Ahmed Nabih Zaki Rashed, “Applications of Conventional and A thermal Arrayed Waveguide Grating (AWG) Module in Active and Passive Optical Networks (PONs),” International Journal of Computer Theory and Engineering (IJCTE), Vol. 1, No. 3, pp. 290-298, 2009. [6] ITU-T Recommendation G.652, “Characteristics of Single Mode Optical Fiber and Cable,” ITU-T Study Group, pp. 1- 14, 2009. [7] Abd El-Naser A. Mohammed, Abd El-Fattah A. Saad, and Ahmed Nabih Zaki Rashed and Mahomud M. Eid, “Characteristics of Multi-Pumped Raman Amplifiers in Dense Wavelength Division Multiplexing (DWDM) Optical Access Networks,” IJCSNS International Journal of Computer Science and Network Security, Vol. 9, No. 2, pp. 277-284, 2009.

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Fiber Raman amplifiers (FRAs) are attractive for ultra wide
dense wavelength division multiplexing (UW-DWDM)
transmission systems due to their advantages of broad
amplification bandwidth and flexible central wavelength. With
recent developments of optical pump sources with high power
near 1.4 µm wavelength and highly nonlinear fiber having a
peak effective Raman gain coefficient more than ten times that
of conventional single mode fiber, distributed FRAs (DFRAs)
are emerging as a practical optical amplifier technology,
especially for opening new wavelength windows such as the
short and ultra long wavelength bands. Optical pump powers
required for Raman amplification were significantly higher than
that for Erbium doped fiber amplifier (EDFA), and the pump
laser technology could not reliably deliver the required powers.
However, with the improvement of pump laser technology
Raman amplification is now an important means of expanding
span transmission reach and capacity. In the present paper, we
have deeply investigated the proposed model for optical
distributed fiber Raman amplifiers in the transmission signal
power and pump power within Raman amplification technique
in co-pumped, counter-pumped, and bi-directional pumping
direction configurations through different types of fiber cable
media. The validity of this model was confirmed by using
experimental data and numerical simulations.

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