5GBPS CWDM-PON ARCHITECTURE FOR LONG REACH UNICAST AND MULTICAST DATA USING HYBRID AMPLIFIER

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1 5GBPS CWDM-PON ARCHITECTURE FOR LONG REACH UNICAST AND MULTICAST DATA USING HYBRID AMPLIFIER Nerkar Narendra N. 1, Kadu Mahesh B. 2 and Labade R.P. 3 1,2,3 Electronics and Telecommunication Department, AVCOE Sangamner,India Abstract- In this paper A hybrid CWDM PON architecture to be implement by means hybrid TDM/WDM network is designed to get high performance from the system and minimise the individual disadvantages of each technique. The multiplexer and demultiplexer FSR periodicity use for transmit Unicast and Multicast traffic on different wavelengths to each Optical Network Unit (ONU). Here We Use the 4 conventional TDM -PON's with 5GB/s bit rate and reach long, sharing a common infrastructure. Here we use the 4 different types of wavelength for unicasting and multicasting of data. For Unicasting a Wavelength is 1290,1310,1330 and 1350nm and for multicasting transmission wavelength is 1490,1510,1530,1550nm. To merge the benefits and compensate the drawbacks of different optical amplifiers, a hybrid amplifier is crate here. The hybrid amplifier is a cascaded semiconductor optical amplifire and Raman amplifier is use here. This paper focuses on the investigation effect of the non-linearity's in the output characteristics, as when we increases the transmission distance. Here this system is simulated on software Optisystem version 13. Keywords Single Mode Fiber, Optical Network Unit, Passive Optical Network I. INTRODUCTION Nowadays, with high growth of internet a need of a high capacity of network systems is felt. Demand for higher bandwidth and capacity have become a much more challenging factor for a service provider. In these conditions optical communication is most favourable medium for delivering data to the user with excellent bandwidth and transmission performance among the existing communication techniques. An optical transmission system suffers from an inherent problem of dispersion. This is the main concern for an optical communication network [1]. WDM optical access network (WDM-OAN), which provide a separate wavelength channel and imply high access bit rate between the optical line terminal (OLT) and each optical network unit (ONU), is considered as one of the most promising approaches to the future OAN [2]. The OAN of typical point-to-multipoint architecture can be divided into the passive optical network (PON) and active optical networks (AON) depending on using passive or active devices in optical distribution network (ODN) and their common structure is shown in Fig. 1 (a) [3]. Multicast function is crucial to WDM-OAN to meet the exponentially increasing demand for applications, such as IPTV and multimedia multicast. Several multicast schemes for WDM-OAN have been proposed [4], [5], [6], which implement the multicast function actually in electronic domain and thus unavoidably limited in power consumption and cost growth. In conventional WDM-OAN, the OLT need to modulate the same data stream to some certain wavelength channels and then transmit to the corresponding ONUs to achieve WDM multicast as shown in Fig. 1 (b), which is actually multicast in the electronic domain. However, for certain multicast services with high speed, sudden burst characteristic and realtime demand (e.g., remote group telemedicine, high definition live program, remote real-time group traffic monitoring), all-optical WDM multicast, which multicast directly in optical domain, can better achieve WDM multicast in WDM-OAN with high speed, real time, fast service provisioning and high resource efficiency. The all-optical WDM multicast function occurring in the OLT or remote node (RN) are illustrated in Fig.1 (c) and (d). Meanwhile, to the best of our knowledge, all-optical DOI: /IJMTER P6FX 8

2 WDM multicast scheme in WDM-OAN has never been reported and discussed its value and scenarios of application in an access network. Fig 1. (a) Typical WDM-OAN architecture; (b) conventional WDM multicast; (c) all-optical WDM multicast from OLT; (c) all-optical WDM multicast from RN.[3] A wavelength division multiplex-passive optical network (WDM-PON) is a promising service of the low cost subscriber networks for the fiber-to-the-home systems. Its upgradability, large capacity and flexibility are its qualities that make it such a promising candidate. Wavelengthdivision- multiplexing transmits multiple data signals using different wavelengths of light through a single fiber. The objective of this work is to implement and propose low cost architectures for high speed performance of passive optical network (PON)[7]. Here we demonstrate an optically amplified extended Coarse Wavelength Division Multiplexing (CWDM) based shared infrastructure for four PONs, one with the standardised PON wavelengths (1490 nm down and 1310 nm up) and the remaining three using downstream and upstream CWDM wavelengths in the 1500 and 1300 nm bands, respectively. Reach extension up to 60 km is accomplished with a bidirectional discrete hybrid SOA-Raman amplifier having at least 75- nm bandwidth in both the upstream and downstream bands (nm total optical bandwidth)[8]. This work improves on by identifying and correcting impairment to upstream performance related to the 1.3µm SOA stage of the hybrid amplifier. The cost of the Optical Network Unit (ONU) is also critical because of the large number of them that are required and the fact that are a dedicated device for each end user. The main novelties of this topology are the use of the FSR of Mux and Demux to transmit multicast data and the tunable laser stack situated at the OLT to send unicast data to the ONUs on time division multiplexing (TDM) basis. This paper focuses on the investigation effect of the non-linearity's in the output characteristics, as when we increases the transmission distance. At last, we check all important parameters like BER, Eye diagram etc, which is satisfied the all require the condition of long distance data transmission. Here this system is simulated on software Optisystem version 13. II. PROPOSED HYBRID CWDM/TDM PON ARCHITECTURE Fig.2 setup of four extended PONs, each serving 128 subscribers with 60-km All rights Reserved 9

3 The network architecture is presented in Fig. 2. In this figure, showing a central office (CO), which sources four PONs; a remote node (RN), including the bidirectional hybrid amplifier, CWDM multiplexing, and passive splitters; and the optical network terminals (ONT) at the subscriber premises. In this figure, we see that the 4 different type of wavelength is sent from CO. Basically these wavelengths are 1490nm,1510nm,1530nm, and 1550nm. All of above wavelengths is used for transmission of multicast data to the 128 subscribers. This system is designed for 60km distance and for 128 users. All 128 users are set to the ONU side of a system. All the wavelengths are combined by using multiplexers and it transmitted via single mode fibers (SMF). The attenuation factor of SMF is 0.2dB\Km[9]. So the at a 20km distance the light signal is attenuated, so here we use the combination of amplifiers, namely Raman amplifier and Semiconductor optical amplifier. Also, dispersion is also one of the main problems of the fiber. Dispersion is reduced by the factor of 16 when moving 2.5Gbps to 10Gbps and by and an additional factor of 16 moving from 10Gbps to 40Gbps[9]. At the receivers side we use the Demultiplexer for separation of wavelengths. Here we use CWDM Demux. From the receivers Side, which also known as ONU side we fix 4 Transmitters, and all these transmitters having wavelength of 1290nm,1310nm,1330nm,1350nm. This all wavelengths are work under 'O' band signals[10]. The free spectral range periodicity of Mux and Demux is use for separation of unicast and multicast data when a transmission is activated. III. EXPERIMENTAL SET UP Figure 3 Central Office or OLT section In the fig.3, basically, 2 separate parts are shown. In this Figure, first parts are optical line terminal. Here In this section, we use the 4 different wavelength transmitters. All this 4 are connected with the ideal Mux. Basically here this ideal Mux use because all data transmitted by transmitters are in ideal conditions. The second part shows basically unicast receiver and also central office part. Here we use the Fork 1*N, This fork has work to separate all the wavelength from transmitter side. At finally we receive the all 4 wavelength, which is filter by Butterworth filter and gives to optical All rights Reserved 10

4 Figure 4 Remote Node In the Fig 4 shows the remote node of fiber. The Central Office is connected to the remote node by 60 km of optical fiber and the remote node is connected to the ONTs by short distribution fibers (drops)[8]. The four passive optical networks operate on following wavelengths (in nm) for multicasting and unicasting communication, respectively: 1490/1310, 1510/1290, 1530/1330, and 1550/1350. As afore said, the 1490/1310 wavelength pair was chosen to coincide with currently standardized TDM PON wavelengths[8]. Also another additional3 wavelength pair on the CWDM grid gives the best chance for cost saving (Particularly in the unicast direction, since the ONT transmitter cost is critical in determining the per-user hardware cost)all of the laser transmitters are commonly available un cooled CWDM DFBs, with a its launch power of approximately 15 dbm, and are directly modulated at 5 Gb/s with PRBS. Figure 5 Optical Network Units All rights Reserved 11

5 In fig 5, It shows the Optical network unit. This is the side of users; Means when data is transmitted from a central office (CO) via remote node (RN) then all data are received at these sections. We see in figure basically it shows that 4 receivers are attach here. From CO we send 4 wavelengths to ONU side so for detection of this all we attached these 4 receivers. The data from CO to ONU is the multicast data. A Multicast of data means two or more Transmitters too many receivers. So here the 128 subscribers are attached for receiving a single wavelength. In above fig 5, we see that the 4 transmitters also attach here. This transmitter s purpose is to transmit Unicast data. The unicast data is received at OLT side. We fix the receivers of unicast data at OLT. The basic meaning of unicasting is one to one transmission. Above system works on the CWDM PON. In the amplifier, subsystem includes two separate Semiconductor Optical Amplifier and Raman hybrid amplifiers (SRA) [6] one for the multicasting wavelength band ( nm) and one for the unicast wavelength band ( nm). Each SRA consists of an Alphion semiconductor optical amplifier (SOA) succeed by a several- km length of Raman fiber with 18.7 m effective area, 0.32 db/km attenuation, ps/nm/km dispersion, and 2.5W /km Raman gain coefficient, all at 1550 nm. The SOAs are angled stripe, buried hetero structure devices, packaged in industry standard 14-pin butterfly packages. The Raman fiber is followed by an optical circulator, which is used to couple in the backward-propagating Raman pump light. Table 1 shows the different parameters that are utilized for the simulation Parameter SMF Dispersion 16 ρs/nm/km Dispersion slope ρs/nm 2 /km Phase Modulation Dispersion coefficient 0.2 ρs/km Effective Area 80 µm 2 Nonlinearity Coefficient 2.6*10-20 Attenuation 0.2 db/km IV. RESULTS AND DISCUSSION In optical communication systems, only optical signal to noise ratio (OSNR) could not accurately measure the system performance, especially in WDM systems. Typically, as a quality factor, Q is a one of the important factors to measure the optical system performance by which to characterize the BER [10]. As a Bit error rate is a total number of bit errors per unit time. BER is unit less quantity which measures the performance of optical transmission system. as it expresses in percentage. For analysis of results, we have used eye diagram. An eye diagram is a graphical representation of the overall performance of optical fiber system. An Eye diagram is actually a voltage diagram that displays numbers of superimposed data pattern that resemble an eye. In eye diagram, basic parameters that are analyzed include Q-factor, BER (bit error rate), Eye height and a threshold value. In this eye height is also called as vertical eye opening and it measures a noise margin of the system. Eye height is given by following formula Eye height = P top - 3*SD top + P base - 3*SD base as, P top = Mean of most predominant peak of histogram for high logic. P base = Mean of most predominant peak of histogram for Low logic. SD top = Standard devation for high logic. SD base = Standard deviation for low logic. (I) Performance analysis for Multicast data 5Gbps Data Rate: All rights Reserved 12

6 Figure (a). Min.log of BER vs. Power (mw) Fig (b) Fig(c) Fig (b). Eye Diagram for 1490nm and1510nm.fig (c). Eye Diagram for 1530nm and1550nm. Figure 6 Multicast Data transmission. In figure 6.(b)and 6(c). we show the eye diagram of 1490nm, 1510nm, 1530nm, and 1550nm wavelength. The fig.6 is for graph between the Min. log of BER vs Power for multicast data transmission. Here we consider the power in the milliwatts. Input optical power is given equal to +15dBm and simulated above design for downstream and upstream data equal to 5Gbps for a distance equal to 60 km When we increase a data rate and distance so optical non- linearity's comes in the picture but we use amplifier here so all this non-linearity will be removed. For the 1490nm the Q- factor is with its BER is equal to 1.37e-27obtain. For the 1510nm, Q-factor is and BER are 8.43e-42. So from above, we see that the results are improve as when we increasing a wavelength. The following table show all detail about transmission of multicast All rights Reserved 13

7 Table 2 Basic Parameter Reading (Multicasting) Parameter 1490nm 1510nm 1530nm 1550nm Q- Factor BER 1.37e e e e-38 BER Height 8.70e e e e-5 Threshold 6.66e e e e-5 Power Input Power 12dBm 12dBm 12dBm 12dBm (II) Performance analysis for Unicast data 5Gbps Data Rate: (1290nm,1310nm,1330nm,1350nm) Fig(a) Received Optical Power(mW) vs Log BER (For 5Gbps) Fig (b). Eye Diagram for 1290nm and1310nm. Fig (c). Eye Diagram for 1330nm and1350nm. Figure 7 Unicast Data transmissions. It is observed eye diagrams for Upstream wavelengths 1290 nm,1310 nm,1330 nm and 1350 nm. This Eye diagram analyzer also displays Q-Factor, Min.BER and Eye height which helps to analyze a performance of upstream data transmission. The eye diagrams for upstream wavelengths are shown in Fig. 7. We have observed min.ber is equal to 0 for transmission of all upstream wavelengths. V. CONCLUSION An optically amplified CWDM-based PON system featuring four extended (60 km) PONs on a common infrastructure (serving 128 subscribers) is presented here. the main motivation of this work is to increase the long haul and ultra-broadband transmission distance, scalability All rights Reserved 14

8 flexibility of the optical networks. In order to achieve these goals, it is of at most importance to optimize the optical hybrid amplifier and placement of optical amplifiers in optical communication systems and networks. This paper focuses on the investigation effect of the nonlinearities in the output characteristics, as when we increase the transmission distance. The performance of hybrid optical amplifiers will be evaluated using the eye patterns, BER measurement, eye opening and Q factor. The parameters such as a number of channels, bit rate, SMF length, attenuation, dispersion, insertion loss, etc were considered with the BER and output receiver power. Eye diagrams were analyzed in terms of BER, eye height, eye opening, jitter and other eye appearance. The receiver output power was compared with transmitted input power to examine how power has wasted. In the future, we also add the another amplifier such as EDFA-SOA, EDFA-Raman for extending the length. REFERENCES [1] K. Thyagarajan, R. K. Varshney, P. Palai, A. K. Ghatak, and I. C. Goyal : A Novel Design of a Dispersion Compensating Fiber. IEEE PHOTONICS TECHNOLOGY LETTERS, VOL. 8, NO. 11, NOVEMBER [2] S. G. Grubb, T. Erdogan, V. Mizrahi, T. Strasser,W. Y. Cheung, W. A. Reed, P. J. Lemaire, A. E. Miller, S. G. Kosinski, G. Nycolak, and P. C. Becker, 1.3_m Cascaded raman amplifiers and their applications, Optical Amplifiers and Their Applications, 1994, Postdeadline paper PD3. [3] Y. Chen, R. Pavlik, C. Visone, F. Pan, E. Gonzales, A. Turukhin, L. Lunardi, D. Al-Salameh, and S. Lumish, 40 nm Broadband SOA-raman hybrid amplifier, in Proc. OFC 2002, Anaheim, CA, Mar. 2002, pp , Paper ThB7. [4] K. C. Reichmann, P. P. Iannone, X. Zhou, N. J. Frigo, and B. R. Hemenway, 240-km CWDM transmission using cascaded SOA raman hybrid amplifiers with 70-nm bandwidth, IEEE Photon. Technol. Lett, vol. 18, pp , Jan. Feb [5] M. D. Feuer, R. D. Feldman, J. L. Zyskind, S. C. Shunk, J. Sulhoff, and T. H. Wood, Remotely-pumped selfamplified star network for local access, in Proc. OFC 1996, San Diego, CA, Feb. 1996, pp , See, for example, Paper WI5. [6] N. Suzuki and J. Nakagawa, First demonstration of full burst optical amplified GE-PON uplink with extended systems budget of up to 128 ONU splits and 58 km reach, in Proc. Europ. Conf. Opt. Commun. (ECOC 2005), Glasgow, Scotland, Sep. 2005, Paper Tu [7] Carlos Bock and Josep Prat, WDM/TDM PON Experiments Using The AWGs Free Spectral Range Periodicity To Transmit Unicast And Multicast Data, 18 April 2005 / Vol. 13, No. 8 / OPTICS EXPRESS [8] P. P. Iannone, K. C. Reichmann, X. Zhou, and S. Grey, Four Extended-Reach TDM PONs Sharing Bidirectional Hybrid CWDM Amplifier", JOURNAL OF LIGHTWAVE TECHNOLOGY, VOL. 26, NO. 1, JANUARY 1, [9] N. Nerkar, M. Kadu and R. Labade, " A Novel Architecture to Reduce Dispersion in Fiber by Using Pre, Post and Symmetrical DCF Methods", ICCASP/ICMMD Advances in Intelligent Systems Research. Vol. 137, Atlantis Press, Pp [10] Govind P. Agrawal, Fiber-Optic Communication System, 3rd edition, Wiley student All rights Reserved 15