ANALYZING DISPERSION COMPENSATION USING UFBG AT 100GBPS OVER 120KM USING SINGLE MODE FIBER

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1 International Journal of Mechanical Engineering and Technology (IJMET) Volume 8, Issue 12, December 2017, pp , Article ID: IJMET_08_12_116 Available online at ISSN Print: and ISSN Online: IAEME Publication Scopus Indexed ANALYZING DISPERSION COMPENSATION USING UFBG AT 100GBPS OVER 120KM USING SINGLE MODE FIBER Ashwani Sharma, Shalini Sharma School of Electrical and Computer Sciences, Shoolini University, Solan (H.P) Ashwani Sharma, Inder Singh School of Computer Science Engineering, UPES, Dehradun (U.K) Suman Bhattacharya Product Evangelist, TATA Consultancy Services ABSTRACT The origin of erbium doped fiber amplifiers (EDFA s) is making the transmission in optical fiber communication more irresistible. But already installed standard non dispersion shifted fibers causing the transmission of data at higher rates to be confined by the immense dispersion unless different compensation technologies are utilized. A number of methodologies have been introduced to resolve this issue, for example, DCF (Dispersion Compensating Fiber), FBG(Fiber Bragg Grating), Electronic Equalizers etc. but an approach to decrease the chromatic dispersion by using FBG can altogether intensify the performance of the system. This paper is demonstrating the use of uniform FBG for compensating dispersion at 100Gbps over a SMF of 120Km by using it in distinct schemes and then on the basis of Q-factor and BER, it has been analyzed that Post dispersion compensation is reducing the effects of dispersion at longer distances with high data transmission rates much better than the remaining schemes. Keywords: Optisystem 7.0; Single mode fiber (SMF) Quality-factor; Bit error rate; Chromatic Dispersion; Uniform Fiber Bragg Grating(UFBG); Inter-symbol interference Cite this Article: Ashwani Sharma, Inder Singh, Suman Bhattacharya and Shalini Sharma, Analyzing Dispersion Compensation using UFBG at 100Gbps over 120km using single mode fiber, International Journal of Mechanical Engineering and Technology 8(12), 2017, pp editor@iaeme.com

2 Analyzing Dispersion Compensation using UFBG at 100Gbps over 120km using single mode fiber 1. INTRODUCTION With the brisk growth in the communication industry all over the world, the optical fiber communication networks with high data rate and high capacity is becoming a vital part in present day communication systems. For the most part, there are three key issues related with the optical fiber systems i.e that is, loss during transmission, nonlinear effects and dispersion. The development of EDFA has reduced the effects caused by transmission loss which was a major problem earlier. But dispersion is a matter of concern when high data rate transmission over long distances is considered [1] Dispersion: Pulses while propagating inside the optical fiber propagates at different velocities and lost their original shape. Due to distinct propagation speeds, they arrive at receiver at distinct time intervals, thereby, causing the pulses to be broadened and overlap with each other. This pulse broadening is called dispersion. Dispersion is a common term related with it and effect is known as inter-symbol interference (ISI). The relation of β with Dispersion parameter (D) is given below in equation (1):- D 2πc λ β 1 When wavelength λλ then the fiber is said to have normal dispersion (β positive. In this dispersion, components having low frequency propagate at a rate faster than components having high frequency. The opposite concept takes place when β negative [2] Dispersion Types: Dispersion can be divided into three types- Intermodal dispersion, Intramodal dispersion (chromatic dispersion) and Polarization mode dispersion Intermodal Dispersion Due to occurrence of delay between higher order and low order modes causes the pulse widening at the receiver and this effect is intermodal dispersion. It is shown in Figure 1. Figure 1 Intermodal Dispersion representation Figure 2 Chromatic Dispersion (CD) Chromatic Dispersion: In single mode fibers, the light pulses comprises of distinct frequency elements and these elements travels inside the optical fiber core with different velocity, thereby, causing pulse widening at the receiver. This phenomenon of pulse widening is called chromatic dispersion. The detailed diagram is shown in Figure Polarization Mode Dispersion: In case of single mode fiber, there are generally two polarization modes exists, which are perpendicular to each other. This is because of the results of birefringence. Every mode has their own speed of propagation which is greater or less than the other causing dispersion, popularly known as polarization mode dispersion as shown in Figure editor@iaeme.com

3 Ashwani Sharma, Inder Singh, Suman Bhattacharya and Shalini Sharma Figure 3 PMD 1.3. Techniques for Dispersion Compensation: There are different techniques which are available for the compensation of dispersion. Fiber Bragg Gratings (FBG) and Dispersion Compensating Fibers (DCF) are the most popular techniques for dispersion compensation Dispersion compensation using DCF: By changing the structure of the fiber, A fiber with negative dispersion value can be designed. And the resultant fiber is termed as Dispersion compensating fibers, [3]. Figure 4 is showing the principle operation of DCF. Figure 4 DCF Technique Dispersion compensation by FBG: It is the most popular technique for dispersion compensation. Fiber Bragg Grating (FBG) allows some of the wavelengths to travel in the forward direction, and reflects others hence, behaving like mirror as shown in Figure 5. Different types of FBG are there like uniform FBG and Chirped FBG. A Grating is called Uniform Grating, if it has constant refractive index modulation period, whereas Chirped FBG contains the variation of the refractive index period with respect to the length [5]. Figure 5 Uniform FBG Fiber Bragg grating provides the dynamic compensation of dispersion. This feature of dynamic compensation is not provided by DCF [6].There are so many advantages of FBG merits over other dispersion compensation techniques like less insertion loss and increased capacity of the optical fiber. [7]. 2. SIMULATION SETUP This paper focuses on the simulations of the Uniform Fiber Bragg Grating in three distinct configurations i.e. Pre compensation, Post compensation and Mix compensation. Eventually, the results are compared in terms of the Q-factor and BER to determine the best configuration among the three. FBG parameters and the Simulation parameters are explained in the tabular editor@iaeme.com

4 Analyzing Dispersion Compensation using UFBG at 100Gbps over 120km using single mode fiber form in the Table-3 and Table-4, respectively. Further the simulation models of three distinct configurations of uniform FBG i.e. Pre, Post and Mix compensation are shown in the Figures- 6, 7 and 8, respectively. This section of the paper shows the execution of Dispersion compensation by utilizing uniform Fiber Bragg Grating as a Dispersion compensator with the help of software naming Optisystem 7.0. This work has been shown for the single channel. Simulation setups are been executed both at the transmitter end and the receiver end. In the transmitter segment, setup is started with a PRBS generator which creates irregular grouping of bits consistently. Then a modulator called Mach-Zehnder modulator, in which one input from non-return to zero (NRZ) modulation format and another input from CW laser, which is behaving as light source, is provided. The modulated optical signals are then transmitted over the optical channel at a rate equivalent to 100Gbps with input power extending from 1dBm to 10dBm. Simulations are completed at a frequency of 193.1THz. Received signals are encounters by pin detector which behaves as transducer i.e. converting the optical signals into the electrical signals. The position of UFBG has been changed to see its effect on the data transmission pulses and bandwidth. The adjustment in the position of UFBG in three unique plans i.e. Pre Compensation, Post Compensation and Mix Compensation. EDFA is likewise utilized as a part of model to reduce attenuation and subsequently utilized after every component of Uniform Fiber Bragg Grating. This paper concentrates on the simulation of the Uniform Fiber Bragg Grating in three different designs i.e. Pre Compensation, Post Compensation and Mix Compensation. Inevitably, the outcomes are looked at as far as the Q-factor and BER to decide the best design among the three. Parameters for UFBG and the parameters for simulation are clarified in the Table-1 and Table-2, separately. Further the simulation models of three particular setups of uniform FBG i.e. Pre, Post and Mix compensation are appeared in the Figures-6, 7 and 8, individually. Table 1 Parameters used for UFBG Sr. No. Parameter Value 1 Length of Fiber 120 Km 2 Noise Threshold -100 db 3 Reflectivity Sample Rate 500 GHz Table 2 General parameters used in Simulation Sr. No. Parameter Value 1 Bit Rate(Gbps) Bandwidth(THz) 1 3 Extinction Ratio(dB) 30 4 Sample Rate(THz) Power(dBm) Gain(dB) 20 7 Noise(dB) 2 8 Frequency(THz) editor@iaeme.com

5 Ashwani Sharma, Inder Singh, Suman Bhattacharya and Shalini Sharma Figure 6 Pre compensation using Uniform Fiber Bragg Grating simulation model Figure 7 Post compensation model Figure 8 Mix compensation model 3. SIMULATIONS RESULTS AND DISCUSSION This part of the paper contains the examination of the results acquired after studying and analyzing the Uniform Fiber Bragg Grating as a Dispersion compensator in three particular setups that are Pre compensation, Post Compensation and Mix compensation. The results are analyzed as per the BER, Q-Factor, Eye height and received power. Figures-9,10 and 11 demonstrating the eye charts of Pre, Post and Mix Dispersion compensation utilizing uniform Fiber Bragg Grating, resp. The indicated eye diagrams are at input power =10dBm as at this power level different schemes of uniform FBG exhibiting the maximum Q-Factor and minimum BER when compared with other power levels from 1dBm to 10dBm. Table-3,4 and 5 is containing the Q-Factor, BER, received power and eye heights of three schemes at different power levels. Figure 9 UFBG Post comp. Figure 10 UFBG Post comp. Figure 9 UFBG Mix comp editor@iaeme.com

6 Analyzing Dispersion Compensation using UFBG at 100Gbps over 120km using single mode fiber Table 3 Results for Pre Compensation of Uniform FBG at inputs from 1dbm to 10dbm Input Power Max Q factor Min BER Eye Height Threshold Received Power(dBm) E E E E E E E E E E E E E E E E E E E E-06 Table 4 Results for Post Compensation of Uniform FBG at inputs from 1dbm to 10dbm Input Power Max Q factor Min BER Eye Height Threshold Received Power(dBm) E E E E E E E E E E E E E E E E E E E E-06 Table 5 Results for mix Compensation of Uniform FBG at inputs from 1dbm to 10dbm Input Power Max Q factor Min BER Eye Height Threshold Received Power(dBm) E E E E E E E E E E E E E E E E E E E E-06 It is observed that Post dispersion compensation is having highest Quality factor and lowest BER (bit error rate) which is the desired condition for the best compensation technique editor@iaeme.com

7 Ashwani Sharma, Inder Singh, Suman Bhattacharya and Shalini Sharma Figure 12 Input Power Vs Q- Factor Plot Figure 13 Power Vs BER Plot Figure 14 Power Vs Eye Height Plot Figure 15 Input Power Vs Received Power Plot By analyzing all the graphs, it is clear that post compensation of uniform FBG Performing batter at 100 Gbps. for 120 Km. 4. CONCLUSION This paper is completely revolved around executing Dispersion Compensation procedure using uniform FBG remembering the true objective to compensate for the dispersion occurs while the transmission of signal over a separation of 120 Km at 100 Gbps. Uniform FBG is used in three particular setups i.e. Pre, Post and Mix Dispersion compensation. Results from the particular courses of action are then analyzed as far as the BER and Q-Factor so as to acquire the best compensation method among them. The diagrams appeared in Fig-12, 13, 14 and 15 are analyzed and it is discovered that the Post Dispersion compensation have predominant Quality Factor and minimum BER when compared with the Pre and Mix compensation of uniform FBG. However, complete removal of dispersion at higher transmission rates is not possible but using Post compensation in uniform FBG can reduced dispersion up to some extent at 100Gbps over 120Km using SMF. REFERENCES [1] P. Lei, J. Shuisheng, Y. Fengping, N. Tigang and W. Zhi, Long Haul WDM system through conventional single mode optical fiber with dispersion compensation by chirped fiber bragg grating, Optic Communications,Elseveir, pp , May,2003. [2] T. Ilavarasan and M. Meenakshi, An overview of fiber dispersion and non lineraity compensation techniques in optical orthogonal frequency division multiplexing systems,journal of Optics,Springer, March, [3] S. Yuhu, Research on the dispersion problem in high speed optical communication systems, IEEE, pp , editor@iaeme.com

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