A HIGH SPEED WDM PON FOR DOWNSTREAM DPSK ASK SIGNALS AND UPSTREAM OOK SIGNAL WITH BROADCAST CAPABILTY

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1 A HIGH SPEED WDM PON FOR DOWNSTREAM DPSK ASK SIGNALS AND UPSTREAM OOK SIGNAL WITH BROADCAST CAPABILTY 1 AAMIR KHAN, 2 ANITA CHOPRA 1 Department of Information Technology, Suresh Gyan Vihar University, Rajasthan, India 2 Department of Electronics & Communication Engineering, Suresh Gyan Vihar University, Rajasthan ABSTRACT A wavelength division multiplexed passive optical network (WDM PON) is a promising advent to realize the flexible data delivery and high capability for access network subscriber. Here we proposed a conventional unicast data and downstream multicast function provided by a wavelength division multiplexed passive optical network (WDM PON). Initially carrier are differentiated and afterward modulated after passed through the beam splitter to broadcast or to deliver the multicast data, while the rest of subcarrier DPSK signals carries the unicast traffic in downstream. High speed wavelength division multiplexed passive optical network (WDM PON) is proposed for downstream DPSK signals, ASK signals and OOK upstream signal with broadcast capability. An experiment on 5 Gb/s ASK,10 Gb/s DPSK downstream signals and 5 Gb/s upstream signal remodulation.at the end of this experiment we observe that error free signal is received at receiver within a range of 20 km. INDEX TERMS: WDM PON (Wavelength division multiplexed passive optical network), OLT (optical line terminal), DPSK (differential phase shift keying signal), MZM (Mech Zehnder modulator), ASK (amplitude phase shift keying), OOK (on off keying), SMF (single mode fiber), BER (Bit Error Rate), ONU (optical network unit). 1. INTRODUCTION Wavelength division multiplexed optical fiber network (WDM PON) is taken as the most promising technique to satisfy the ever increasing bandwidth requirement for the next generation technology. It is necessary to bring broadband services highly cost effective INTERNATIONAL JOURNAL OF SCIENCE, ENGINEERING AND TECHNOLOGY

2 which gratify the fast growing demand for access network bandwidth and to minimize the degradation in performance occurs due to impairment during transmission, as well as to maximize the capacity of system. Because of the active growth of capacity requirement for long distance transmission, wavelength division multiplexed passive optical network (WDM PON) has been considered as an alluring solution to upgrade the existing access network in order to confront with exponential increase bandwidth demand. These networks should have the capability to provide the manifold services such as high definition television (HDTV) broadcasting, video on demand, video conferencing services. Apparently several approaches have been proposed to empower broadcasting or multicasting function in WDM PON. The multicast services can be implemented or multiplexed by a conventional unicast traffic by time division multiplexing which experienced a complain of complicated scheduling and dimished bandwidth. Broadcast capability can also be increased by using a additional light sources which result in increased cost and complexity. Subcarrier multiplexing or hybrid modulation technique are other proposed schemes which requires a eminent frequency electrical components at the optical network (ONU) unit or encounters a interference between two formats in downstream signal delivery, respectively. Here, In this investigation we purported and experimentally projected the feature of broadcasting and multicasting in high speed WDM PON for downstream DPSK ASK signals and upstream OOK signals with colorless optical network units (ONUs). For each WDM PON channel, a phase modulator is used which modulate the signal which is thereafter splitted in two parts by power beam splitter (1x2), Mech Zehnder modulator is also used to remodulate the signal, which reduces the interference between them, that results in delivering a downstream multicast data with minimum error at receiver side. 2. ARCHITECTURE AND EXPERIMENT In this figure, we have experimentally showed the feasibility of proposed broadcast enabled WDM PON to optical network units (ONUs). Experimental setup shows the proposed architecture for broadcasting enabled WDM PON transmission scheme in which we have used a SMF of length 20km for upstream INTERNATIONAL JOURNAL OF SCIENCE, ENGINEERING AND TECHNOLOGY

3 and downstream transmisson in figure 1. An NRZ DPSK formats at 10 gigabits is used to modulate a CW laser diode at 1550 nm to use for the generation for downstream data. In our experiment, pulse pattern application is used to generate the electrical data, that means it requires a number of antennas and boundless distributed fiber network for wireless network. Because of this colorless RAU with concentric optical carriers allocation could be a covenant cost effective candidate. Figure 1: Architecture of a highh speed WDM PON with broadcast capability The optical modulation is bring to successful conclusion by using a Mach Zehnder modulator biased at least possible transmission count and directed by 2vp pinnacle data signal. Intensity remains constantt as long as phase modulation achieved between 0 and p. Signal attained by phase modulation is introduced into the fiber optic link using a multiplexer of spacing 100 GHz and 4 db injected loss to stimulate a WDM central office (CO). Single mode fiber (SMF) of length 20 km is used which is followed by multiplexer in the remode node. At the ONU, the downstream signal is splitted or divided INTERNATIONAL JOURNAL OF SCIENCE, ENGINEERING AND TECHNOLOGY

4 into 2 sub streams using power splitter (1x2). In upper sub stream, signal is amplified by Erbium Doped Fiber Amplifier (EDFA) foregoing uses a coupler to split the signal, so that the signal can be detected by DPSK demodulator at the receiver end (Single End Receiver). The rest of part from coupler is feed to Mech Zehnder modulator (MZM) proceeded by optical power meter that modulates the upstream transmission at 5 Gbit/s which is being computed by BER (bit error rate) analyzer. The other splitted signal coming from power splitter is feeded to NRZ pulse generator which produces a pulse signal, followed by Mech Zehnder modulator which produces a optical modulation that is also foregoing by optical power meter that modulates the upstream transmission at 5 gbit/s at receiver end which is being computed through BER (bit error rate) analyzer. (a) (b) (c) (d) INTERNATIONAL JOURNAL OF SCIENCE, ENGINEERING AND TECHNOLOGY

5 (e) Figure 2: BER Measurement of (a) Input Optical power, (b) Received downstream Optical power (c) Received Upstream Optical power. Eye Diagram of (d) 10Gbps Downstream DPSK (e) 5Gbps Upstream OOK 3. RESULT In figure 2 (a), we have observed the BER (bit error rate) measurement of the input signal at back to back (B2B) and after the single mode fiber transmission, with the close similar pattern after the transmission of signals. We get the result in which as we increase the input power, the reception of signal improves by using the graph. In figure 2(b), we have observed the BER (bit error rate) measurement of the input signal at back to back (B2B) and after the single mode fiber transmission, with the close similar pattern after the transmission of signals. Here, we measure the graph of received optical fibre vs log(ber) and we concluded a 0.3 db power penalty due to the optical link transmission of 20 km. For 20 km fibre, we get a clear signal received at receiver without any dispersion. In figure 2 (c) we have observed the BER measurement of the signal (downstream) at back to back and with the close similar patterns after the transmission signal. Here we compared the received optical fiber and log (BER) using a graph, and get a 0.5 db power penalty due to 20 km transmission. INTERNATIONAL JOURNAL OF SCIENCE, ENGINEERING AND TECHNOLOGY

6 4. CONCLUSION We have experimentally demonstrated the proposed WDM PON architecture that provide multicast enabled downstream over the conventional unicast data service. The multicast function for all channels can be dynamically reconfigured by centralized control in optical line transmission (OPT). The remodulation technique unemploys the use of additional light source and colored components which results in minimum loss in signal within 20 km OFL as well as effective reduce in cost and complexity. REFERENCE [1] G. Talli, C.W. Chow, E.K. MacHale, P.D. Townsend, Long reach hybrid DWDMTDM PON with high split ratio employing centralized light source, J. Opt. Network.6 (2007) [2] H.D. Kim, S.G. Kang, C.H. Lee, A lowcost WDM source with an ASE injected Fabry Perot semiconductor laser, IEEE Photon. Technol. Lett. (2000) [3] L.Y. Chan, C.K. Chan, D.T.K. Tong, F. Tong, L.K. Chen, Upstream traffic transmitter using injection locked Fabry Perot laser diode as modulator for WDM access networks, Electron. Lett. (2002). [4]. E. S. Son, K. H. Han, J. K. Kim, and Y. C. Chung, Bidirectional WDM passive optical network for simultaneous transmission of data and digital broadcast video service, J. Lightw. Technol. (2003). [5]. J. H. Moon, K.M. Choi, and C. H. Lee, Overlay of broadcasting signal in a WDM PON, in proceedings of Optical Fiber Communication. [6]. T. Y. Kim and S. K. Han, Reflective SOA based bidirectional WDM PON sharing optical source for up/downlink data and broadcasting transmission, IEEE Photon. Technol. Lett. 18, , (2006). INTERNATIONAL JOURNAL OF SCIENCE, ENGINEERING AND TECHNOLOGY