In this work, we use the generalized nonlinear Schrödinger equation to study propagation of ultrashort optical pulses in the presence of self-phase modulation, nonlinear absorption and third-order dispersion. The combined effect of the third-order dispersion and nonlinear absorption on amplitude, center location and phase of the soliton has investigated by approximate analytical method. Full Text: PDF References Govind. P. Agrawal, Nonlinear Fiber Optics, Academic Press, San Diego (California), 2001. DirectLink Hasegawa. A, M. Matsumoto, Optical solitons in fibers, Springer-Verlag Berlin Heidelberg 2003. CrossRef G. Tsigaridas, I. Polyzos, V. Giannetas and P. Persephonis, "Compensation of nonlinear absorption in a soliton communication system", Chaos, Solitons & Fractals, Vol. 35, 2008, pp.151-160. CrossRef Haus H., "Optical-fiber solitons, their properties and uses", P. IEEE 81:970-83 (1993). CrossRef Chan VWS, Hall KL, Modiano E, Rauschenbach KA., "Architectures and technologies for high-speed optical data networks", J Lightwave Technol 16:2146-68 (1998). CrossRef Newhouse MA, Weldman DL, Hall DW, "Enhanced-nonlinearity single-mode lead silicate optical fiber", Opt Lett, vol.16, 1185 (1990). CrossRef Okuno T, Onishi M, Kashiwada T, Ishikawa S, Nishimura M., "Silica-based functional fibers with enhanced nonlinearity and their applications", IEEE J Sel Top Quant, Vol. 5, 1385(1999). CrossRef G. I. Stegeman, in Contemporary Nonlinear Optics, edited by G. P. Agrawal and R. W. Boyd (Academic, San Diego), 1992. M. A. Newhouse, D. L. weidman, and D. W. Hall, "Enhanced-nonlinearity single-mode lead silicate optical fiber", Opt. Lett. Vol,15, 1185 (1990). CrossRef M. A. Newhouse, in Proceedings of a Symposium on Optical Waveguide Materials, Boston, 1991. Dinh Xuan Khoa, Bui Dinh Thuan, "Influence of loss and high-order dispersion on soliton?s transmision in optical fibers", Communications in Physics, Vol.17, 17 ? 22 (2007). DirectLink