All rights reserved by www.ijaresm.net ISSN : 2394-1766 1 IMPROVING LINK PERFORMANCE BY ANALYSIS OF NONLINEAR EFFECTS IN FIBER OPTICS COMMUNICATION Hirenkumar A. Tailor 1 , Antrix Chaudhari 2 , Nita D. Mehta 3 Assistant Professor, EC Dept., S.N.P.I.T & R.C, Umrakh, Bardoli, Gujarat, India 1 PG. Student, EC Dept., Dr. S & S S Ghandhy Govt. Engg. College, Surat, Gujarat, India 2 Asso. Prof., EC Dept., Dr.S & S S Ghandhy Govt. Engg. College, Surat, Gujarat, India 3 Abstract: In order to expand the capacity of optical fiber communication system the most important phenomena is the emergence of wavelength division multiplexing (WDM). Using WDM, multiple channel of information can be transmitted on single fiber. There are some limiting factors related to data rate and capacity in WDM optical fiber communication system. These limiting factors can be linear or non-linear. The most important non-linear effect occur in the fiber optics communication system are Self phase modulation (SPM), Cross phase modulation (XPM) and Four wave mixing ( FWM). Self phase modulation (SPM) occurs only in single channel fiber optics communication system and Cross phase modulation (XPM), Four wave mixing (FWM) have impact on multichannel WDM fiber communication system. In this paper, we analyze the impact of Self phase modulation (SPM), cross phase modulation (XPM) on WDM communication system for different parameters. We also describe some novel technique to reduce the effect of these nonlinearities (SPM, XPM) in WDM fiber communication system. Keywords: Cross phase modulation (XPM), Four wave mixing (FWM), Optical fiber communication, Self phase modulation (SPM). I. INTRODUCTION The terms linear and nonlinear in optics mean intensity independent and intensity dependent phenomenon respectively. As long as optical power within the fiber is small, fiber can be treated as a linear medium that is loss and refractive index are independent of signal power [1]. But when power level in the system increases nonlinear effect comes into picture. Nonlinearity effects arose as optical fiber data rates, transmission lengths and optical power level increases [2]. Nonlinear effects in optical fiber occur due to change in the refractive index of the medium with optical intensity. The power dependence of refractive index is responsible for the kerr effect [1]. There are three types of fiber nonlinearities due to the Kerr effect namely (i) Self phase modulation (SPM) (ii) Cross phase modulation (XPM) (iii) Four wave mixing (FWM).