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Binh, Optical Fiber Communication Systems: Overview of Modeling Techniques for Optical Transmission Systems, CRC Press, 20xx. [10] W. Kaiser, T. Wuth, M. Wichers, W. Rosenkranz, Reduced plexity optical duobinary 10 Gb/s transmitter setup resulting in an increased transmission distance, Photon. Technol. Lett. (20xx). [11] . Lee, . Messerschmitt, Digital Communication 2/e, Kluwer Academic Publishers, Norwell, MA, USA, 1994. 桂林電子科技大 學(xué)畢業(yè) 設(shè)計（論文）報告用紙 第 9 頁 共 29 頁 Transmission performance on frequency response of receivers and chirping shape of transmitters for 10Gb ? s LiNbO3 modulator based lightwave systems AbstractWe report transmission performance depending on frequency response of receivers and chirping shape of transmitters for10Gb ? s LiNbO3 modulator based light wave systems. By solving the nonlinear Schrodinger equation including developed chirping and extinction ratio(ε) models for transmitters, and frequency response and noises for receivers, we have evaluated transmission performance by bit error rate ( BER ). and eye opening penalty ( EOP ). Calculated BER and EOP characteristics are pared to the measured BER characteristics so that we can find which bination between chirping model and frequency response for receivers is the best model to estimate the tendency in sensitivity degradation similar to the measured BER characteristics. The simulation results suggest that calculated BER characteristics using the Bessel–Thomson filter as a receiver frequency response model provide better prediction to estimate system performance. Furthermore, different chirping models may be used for positive and negative chirp parameters for better estimation of BER. 1 Introduction As current optical transmission systems are being more and more plex, and demand for munication services is growing at a higher speed than ever experienced before, simulation tools can provide efficient and fast system design, and therefore systems are implemented with less time and cost. So, many papers have been reported about light wave system simulations [1–10]. In highspeed optical transmission system, intensity modulated pulse is distorted by fiber dispersion, fiber nonlinearity, and transient chirping of transmitters. Moreover, frequency response characteristics of receivers have an important impact on the inter symbol interference at the input of the decision circuit, which can cause additional signal distortion. Therefore, in order to estimate accurate transmission performance, receiver characteristics as well as waveform distortion must be considered. Estimating transmission performance, eye opening penalty ( EOP ). and bit error rate ( BER ). can be used in optical transmission system simulation. EOP can be calculated from only signal distortion by chirping and fiber dispersion, while BER is based on performance degradation caused by receiver characteristics as well as signal distortion due to interaction between chirping and fiber dispersion. Signal distortion by linear and nonlinear effects of fiber—fiber loss, group velocity 桂林電子科技大 學(xué)畢業(yè) 設(shè)計（論文）報告用紙 第 10 頁 共 29 頁 dispersion, and selfphase modulation—can be well modeled by the nonlinear Schrodinger equation [11]. Chirping of Mach–Zehnder type LiNbO3 based transmitters can be modeled by two methods: one is calculated by the voltage ratio applied to the two electrodes [12], and the other is proposed by Koyama and Iga [13]. Chirping generated by each method is little different, which can make a difference in transmission performance. As frequency response of receivers, low pass filters are usually used for receiver models [2–10]. Frequency response of receivers can be assumed to be ideal [2], the Butterworth filter[3,4], the Bessel–Thomson filter [5,6], the Gaussian filter [7,8], and measured receiver characteristics [9,10]. The Bessel–Thomson filter is monly used in order to minimize group delay distortion by its linear phase characteristic [14]. In this paper, we report on transmission performance by calculated BER and EOP from two different chirping models of LiNbO3based transmitters and two different frequency response characteristics of receivers. These calculated BER and EOP are pared with the measured BER so that we can find the best model to estimate the tendency in sensitivity degradation similar to the real system performance ( measured BER characteristics ). 2 Modeling of the 10Gbps transmission system Chirping and extinction ratio of transmitters For Mach–Zehnder 10Gbrs LiNbO3 external modulators, chirping and extinction ratio of the transmitter are varied by adjusting voltages applied to two electrodes. Two different chirpings are calculated from different α parameters used in LiNbO3