DOI 10.1515/joc-2013-0035 J. Opt. Commun. 2013; aop Muhammad Idrees Afridi*, Yousaf Khan, Noaman Ahmad Khan, Jahanzaib Khan and Shahid Latif Simultaneous Demultiplexing and Demodulation of 10 Gbit/s RZ-DPSK Signal using Arrayed Waveguide Gratings Abstract: We propose and demonstrate simultaneous demultiplexing and demodulation of wave length divi- sion multiplexed (WDM) return-to-zero differential phase- shift keying (RZ-DPSK) signal by a standard Arrayed Waveguide Gratings (AWG) at 10 Gbit/s data rate using ITU grid of 100 GHz channel spacing. Simulation results show error free transmission in a distance of 25 km with negligible power penalty and improved receiver sensi- tivity. The propose scheme is cost effective in term of component counts, hence reduces the deployment cost significantly. Keywords: wave length division multiplexing, demod- ulation, demultiplexing, differential phase shift keying, arrayed waveguide gratings PACS ® (2010). ■■ *Corresponding author: Muhammad Idrees Afridi: Department of Electrical Engineering, Iqra National University Hayatabad, Peshawar, Pakistan. E-mail: midreesafridi@gmail.com Yousaf Khan, Noaman Ahmad Khan, Jahanzaib Khan, Shahid Latif: Department of Electrical Engineering, Iqra National University Hayatabad, Peshawar, Pakistan 1 Introduction Differential phase shift keying (DPSK) is an attractive modulation format because of its high robustness to non linear propagation [1]. Optical DPSK signal can be de- tected by different kind of receivers. The Common opera- tion among all the receivers is the translation of optical signal into electrical signal by photo diode. In DPSK trans- mission, the information is stored in phase of the signal, which needs to be converted into intensity because photo diode can easily detect variation in amplitude. In recent years, various schemes have been proposed to demodu- late the DPSK signal efficiently at the receiver. Mach Zehnder Delay Interferometer (MZDI) has been widely used for demodulation of DPSK signal in direct detection DPSK receiver [2]. However, MZDI has phase stabilization and practical realization issues due to polarization match- ing and temperature distortion. Optical filters were inves- tigated and reported to achieve DPSK demodulation for being much simpler and more stable component to realize. It has reported that when duo-binary coding is used in- stead of binary coding, the same function can easily be realized with band pass filter having same bandwidth [3, 4]. Demodulation of NRZ-DPSK at 10 Gbit/s and 40 Gbit/s by means of frequency periodic filtering has been also reported [5]. However, all these filtering techniques need an additional DPSK demodulator in WDM system which ultimately increase the system deployment cost. In WDM demultiplexing, signals separation are made by filters, which shows that the signals are filtered in two steps i.e. channel separation with FBG Gaussian shaped filter and then followed by WDM demultiplexer [6]. It is proposed to integrate both these functionalities into a single filter, the one which is integrated in demultiplexer. In this paper, we demonstrate simultaneous de- multiplexing and demodulation of 10 Gbit/s WDM RZ- DPSK signal using an AWG with ITU-grid of 100 GHz channel spacing. Our propose scheme is effective in term of the component counts. With N number of multiplexed channels, this solution only requires 2 numbers of AWGs instead of N numbers of channel selecting filters and N numbers of MZDI. More ever N numbers of standard photo detectors are required instead of N numbers of balanced photo detectors. Compare with conventional demodula- tion schemes of using MZDI or filters, the AWG offers the advantages of low insertion losses, good cross talk levels, polarization insensitivity and high fiber coupling effi- ciency. The simulation model used for evaluation is based on optisystem.v.8.0. The simulation results such as Quality Factor and BER are being analyzed. The rest of the paper is divided in four sections. Section 2 describes the Theory and working principle, Section 3 presents the simulation setup and operation, Section 4 discusses the transmission performance and analysis and finally section 5 summa- rizes the paper with conclusions. (CS6) WDG (210×280mm) DGMetaScience J-2749 JOC pp. 1–6 JOC_d0035-1443 (p. 1) PMU:(idp) 15/7/2013 12 July 2012 2:14 PM 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 Please supply PACS number Pls verify all affilia- tions