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Propagation of femto-second or subfemto-second opticalpulses in single mode fibers is of interest in opticalcommunication because of its potential for high datarate transmission systems, especially when shapes ofenvelope of the pulses remain constants (solitons). Insuch short time regime, evolution of envelope of thepulses is described by the so called GeneralizedSchrödinger Equation (GNSE) which takes into accountnonlinear effect as Self Phase Modulation (SPM),Group Velocity Dispersion (GVD), Third OrderDispersion (TOD), and Stimulated Raman Scattering(SRS). In this paper we search soliton solutions for theGNSE in the presence of all above nonlinear effects byuse of Jacobian expansion. We find several ranges forthe above nonlinear effects in which solitonspropagation can be maintained.Người trình bày: Thái Thị Minh Nguyệt82. Investigation Of Wavelength Shifting In TheDFB Laser With Two Sections By UsingInjection Current I2 Into Saturable AbsorberSectionNguyễn Văn Phú, Đinh Văn HoàngIn this paper we study of wavelength shifting in theDFB laser with two sections by using injection currentI2 into the saturable absorber section. By using theinjection current I2, we investigated the mode of lasergeneration of the DFB laser with two sections.Thành phố Đồng Hới (03- 06/8/2009) Trang 73/ 102We found the suitable parameters for experimentalprocedure to application of the two sections DFB laserin the optical communication.Người trình bày: Nguyễn Văn Phú83. Matching of Pump and Mode volumes insideLaser Diodes side-pumped Laser RodNguyễn Văn Hóa, Hồ Quang Quý, Vũ Ngọc SáuMismatching of the pump volume and mode volumeinside active rod is an important effect, which influencesthermal effect, periodical induced refractive index, andthen efficiency of laser generation. To avoid it, it needsto choice a optimal collection of basical parameters ofpumping laser diodes and of cavity. By transfer matrixof optical elements and cavity theory, an equationdiscribed relation between transverse waist of pumpintensity inside laser rod and waist of Gaussian modeTEM00 of laser cavity is adressed. Using simulationmethod, the optimal value of parameter is calculated anddiscussed. The results give us a suitable choice forexperiments in the furture.Người trình bày: Hồ Quang Quý84. Four-level Model For EIT of Cold 85^RbVũ Ngọc Sáu, B. Brzostowski, Cao Long Vân,Đinh Xuân Khoa, B. GrabiecIt is shown by theoretical model describing interactionof strong electromagnetic filed with four-level atomicsystem of cold 85Rb that a multiple windows ofThành phố Đồng Hới (03- 06/8/2009) Trang 74/ 102