Global Journal of researches in engineering Electrical and electronical engineering Volume 11 Issue 5 Version 1.0 Type: Double Blind Peer Reviewed International Research Journal Publisher: Global Journals Inc. (USA) Online ISSN: 0975-5861 Analysis of Techniques for Wavelength Conversion in Semiconductor Optical Amplifier By Rajiv Mahajan,Harmanjot Singh Sai Institute of Technology, Amritsar, Punjab, India. Abstracts - In this paper we focus our attention on the affect of Confinement Factor and SOA Length, two important parameters of Semiconductor optical amplifiers (SOA) for wavelength conversion. There are many functional applications for SOAs, one of which is wavelength conversion. We represent two wavelength conversion mechanisms using SOA (Semiconductor Optical Amplifiers), these are FWM (Four wave Mixing) and Cross Gain Modulation (XGM). We analysis Q value for both the techniques and also represent them with the help of Maximum Eye Opening. Keywords: Semiconductor optical amplifiers (SOA), Four wave Mixing (FWM), Cross Gain Modulation (XGM), cross-polarization modulation (XPolM), Quality Value (Q value), Bit Error Rate (BER) GJCST Classification : 090606 Analysis of Techniques for Wavelength Conversion in Semiconductor Optical Amplifier Strictly as per the compliance and regulations of: 11 Rajiv Mahajan,Harmanjot Singh This is a research/review paper, distributed under the terms of the Creative Commons Attribution-Noncommercial 3.0 Unported License http://creativecommons.org/licenses/by-nc/3.0/), permitting all non commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Analysis of Techniques for Wavelength Conversion in Semiconductor Optical Amplifier Rajiv Mahajan α,harmanjot Singh Ω Abstract - In this paper we focus our attention on the affect of Confinement Factor and SOA Length, two important parameters of Semiconductor optical amplifiers (SOA) for wavelength conversion. There are many functional applications for SOAs, one of which is wavelength conversion. We represent two wavelength conversion mechanisms using SOA (Semiconductor Optical Amplifiers), these are FWM (Four wave Mixing) and Cross Gain Modulation (XGM). We analysis Q value for both the techniques and also represent them with the help of Maximum Eye Opening. Keywords : Semiconductor optical amplifiers (SOA), Four wave Mixing (FWM), Cross Gain Modulation (XGM), cross-polarization modulation (XPolM), Quality Value (Q value), Bit Error Rate (BER) I. INTRODUCTION All-optical wavelength converters with 2R regeneration capabilities, that allow operation at speeds beyond the limits of electronic devices, will be essential in future wavelength division multiplexing (WDM) networks. Of particular interest are simple and compact wavelength converters that help to avoid wavelength blocking and facilitate WDM network management. All-optical wavelength conversion has successfully been demonstrated with semiconductor optical amplifier (SOA) devices exploiting the cross-gain modulation (XGM) effect as well as the Four Wave Mixing (FWM) effect. All these can be realized by using fibre nonlinearities or nonlinearities in semiconductor devices. SOAs have generated more and more interest when optical signal processing is involved. Hence, they are exploited to achieve functional devices in wavelength conversion at high bit rates [1], which is a very important function in conjunction with WDM systems. This makes them very useful in wavelength routers to manage wavelength paths through optical networks based on complex meshes as compared to point-to-point architectures [2]. Many studies have paid more attention on SOAs performance for implementing and configuring wavelength conversion schemes. The optical wavelength converters based on SOA nonlinearities have been proposed and discussed, such as cross - gain modulation (XGM) [2], cross - phasemodulation (XPM) [3,4], four-wave mixing (FWM) [5,6]. Each configuration has its advantages and disadvantages; and then its framework of application in optical communication networks. II. CONCEPT OF WAVELENGTH CONVERSION WDM technology is being extensively deployed on point-to point links within transport networks in the United States, while WDM point-to-point links are soon to be deployed within Europe [13]. However, WDM promises advantages for switching and routing as well as for transmission. Optical cross-connects are currently being developed which can switch an entire wavelength from an input fiber to an output fiber. Particularly, simple and compact wavelength converters that help to avoid wavelength blocking [7]. All-optical wavelength conversion has successfully been demonstrated with semiconductor optical amplifier (SOA) devices exploiting the cross gain modulation (XGM) effect as well as the cross- phase modulation (XPM). In the crossgain modulation scheme a strong input signal is used to saturate the gain of a SOA and thereby to modulate a CW signal carrying the new wavelength [8]. Although XGM is limited by the relatively slow carrier recovery time within the SOA, impressive wavelength conversion of up to Gbits/s [8], has been demonstrated. XGM is accompanied by large chirp and low extinction ratios [8]. Wavelength converter changes the input wavelength to a new wavelength without modifying the data contents of the signal. Many schemes were developed during 1990 s for making wavelength converters [10, 11]. Two of them are discussed here (XGM and FWM) [11] ( f ) V 9Global Journal of Researches in Engineering Volume XI Issue vv Version I Author α : Assistant Professor, Amritsar College of Engineering & Technology Amritsar, Punjab, India. Author Ω : Lecturer Sai Institute of Technology, Amritsar, Punjab,India. Figure 1 : Basic Diagram for Wavelength Conversion
10 Global Journal of Researches in Engineering ( f ) Volume XI Issue V Version I 55 50 45 35 25 15 1 1.5 2 2.5 3 3.5 4 4.5 SOA Length (mts.) x 10-4 38 36 34 32 28 26 24 22 0.3 0.32 0.34 0.36 0.38 0.4 0.42 0.44 0.46 0.48 0.5 Confinement factor III. (a) a Q a ue s Co e e t acto G ec que a Q a ue Co e e t acto G ec s que (b) (C) RESULTS Confinement Factor = 0.1 Confinement Factor = 0.2 Confinement Factor = 0.3 Confinement Factor = 0.4 Confinement Factor = 0.5 SOA Length 0.0001 m SOA Length 0.0002 m SOA Length 0.0003 m SOA Length 0.0004 m Fig.2. Wavelength conversion using XGM; (a) maximum Q vs. SOA Length (m) when for Confinement Factor is varied (b) Maximum Q vs. Confinement Factor when SOA length is varied (c) Eye Opening for XGM. We studied the maximum Q value responses for both Cross Gain Modulation (XGM) and Four Wave Mixing (FWM) techniques. The gain recovery time is inversely proportional to the confinement factor. Hence higher the value of confinement factor the shorter is the gain recovery time [12,13]. The response for Q value is represented with respect to either SOA Length in meters or Confinement factor. In Figure 2(a) results are shown for XGM. Here the maximum value of Q is represented with respect to length of SOA in meters and it is noted that for value of confinement factor= 0.2 maximum value of Q is obtained and for confinement factor=0.1 the value of Q decreases up to SOA length = 0.0002 and then remains constant. For higher confinement factors of 0.2, 0.3 and 0.4 the value of maximum eye opening remains almost constant with increase in length of SOA. The length of SOA increases it will also corresponds to increase the input power energy for a fixed gain compression.[12,13] Figure 2(b) represents the different graphs at SOA Length varying from 0.0001 meters to 0.0004 meters. The results are shown for maximum value of Q to the confinement factor. From the diagram it is cleared that with increase in confinement factor the Q value goes on decreasing. Figure 2(c) shows the Eye Diagram for XGM when the value of SOA Length = 0.0004 meters and the maximum value of Q is achieved at Confinement Factor = 0.3. As shown in the diagram the Eye open s very clearly for the above given values. Max. Q Factor 70 60 50 a u Q a ue s Co e e t acto 10 0.3 0.32 0.34 0.36 0.38 0.4 0.42 0.44 0.46 0.48 Confinement Factor in FWM 160 1 1 100 80 60 0 - (a) a Q acto s SO e gt (b) SOA Length =0.0001 (m) SOA Length =0.0002 (m) SOA Length =0.0003 (m) SOA Length =0.0004 (m) SOA Length =0.0005 (m) SOA Length =0.0006 (m) Confinement Factor = 0.1 Confinement Factor = 0.2 Confinement Factor = 0.3 Confinement Factor = 0.4 Confinement Factor = 0.5 Confinement Factor = 0.6 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 SOA Length (mts.) x 10-4 (c) Fig. 3. Wavelength conversion using FWM; (a) maximum Q vs. SOA Length (m) when for Confinement Factor is varied (b) Maximum Q vs. Confinement Factor when 0.5
SOA length is varied (c) Eye Opening for FWM. In figure 3(a) graphs are obtained for FWM technique and represent the Maximum value of Q to the Confinement Factor for different values of SOA Length. The graph shows the Q value from 0.3 to 0.5. Different graphs are shown for SOA Length = 0.0001 meters to 0.0006 meters. Figure 3(b) represents the graphs are obtained for FWM technique and represents the Maximum value of Q to the SOA Length in meters for different values of Confinement Factor. The Q value is shown for SOA Length = 0.0001 meters to 0.0006 meters. The study of graphs is done at different values of Confinement Factors from 0.1 to 0.6. The Value of Q decreases for confinement factor=0.1 up to SOA length= 0.0002 meters and remains almost constant for higher values. Eye Diagram for FWM as shown in figure 3(c), when the value of SOA Length = 0.0003 meters and the maximum value of Q is achieved at Confinement Factor = 0.3. At these values the Eye is very clear. IV. CONCLUSIONS From the above study we have concluded that wavelength conversion is achieved by both XGM and FWM techniques. If the value of confinement Factor is kept same than FWM will give optimum value of eye opening at 0.0003 meters of SOA length as that in case of XGM the optimum value is achieved for same Confinement Factor at 0.0004 meters of SOA length. Although the value of Q is greater in case of XGM than that of FWM. More over the Maximum Eye Opening in db shows that the optimum result is obtained at confinement factor = 0.3 and SOA Length = 0.0003 meters in both the cases of XGM and FWM. REFERENCES RÉFÉRENCES REFERENCIAS 1. Y. Said, H. Rezig and A. Bouallegue, Performance Evaluation of Wavelength Conversion Using a Wideband Semiconductor Optical Amplifier at Gbit/s, The Open Optics Journal, vol. 4, pp. 21-28, 10. 2. Wei CC, Huang MF, Chen J., Enhancing the frequency response of cross-polarization wavelength Conversion, IEEE Photon Technol Lett., vol. 17, pp. 1683 85, 05. 3. Matsumoto A, Nishimura K, Utaka K, Usami M., Operational design on high-speed Semiconductor optical amplifier with assist light for application to wavelength converters using cross-phase modulation, IEEE J Quantum Electron, vol. 42, pp. 313-23, 06. 4. Fu S, Dong J, Shum P, Zhang L, Zhang X, Huang D., Experimental demonstration of both inverted and non-inverted wavelength conversion based on transient cross phase modulation of SOA, J Optics Express, vol. 14, pp. 7587-93, 06. 5. Contestabile G, Presi M, Ciaramella E., Multiple wavelength conversion for WDM Multicasting by FWM in an SOA, IEEE Photon Technol. Lett., vol. 16, pp. 1775-77, 04. 6. Politi C, Klonidis D, O Mahony MJ., Dynamic behaviour of wavelength converters based on FWM in SOAs, IEEE J Quantum Electron., Vol. 42, pp. 108-25, 06. 7. J. Leuthold, C.H. Joyner, B. Mikkelsen, G. Raybon, J.L. Pleumeekers, B.I. Miller, K. Dreyer and C.A. Burrus, 100Gbit/s all-optical wavelength conversion with integrated SOA delayed-interference configuration, Electronics Letters, vol. 36, June, 00. 8. Contestabile,G. et al, Cross-Gain Modulation in Quantum-Dot SOA at 1550 nm, IEEE, Dec., 10. 9. InPhenix, Inc., The Enhanced Functionalities of Semiconductor Optical Amplifier and their role in Advanced Optical Networking, June,10. 10. Govind P. Agrawal., Fiber-Optic Communications Systems, Third Edition. 02. 11. Leuthold J, Joyner CH, Mikkelsen B, et al., 100Gbit/s all-optical wavelength conversion with integrated SOA delayed-interference configuration, Electron Lett., vol. 36, pp. 1129-, 00. 12. Politi C, Klonidis D, O Mahony MJ., Dynamic behaviour of wavelength converters based on FWM in SOAs, IEEE J Quantum Electron, vol. 42, pp.108-25, 06. 13. Jennifer M. Yates and Michael P. Rumsewicz., Wavelength Converters in Dynamically Reconfigurable WDM Networks, IEEE Communications Surveys, Second Quarter 1999. ( f ) V 11 Global Journal of Researches in Engineering Volume XI Issue vv Version I
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