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Soliton generation in optical fibers has been generally studied through the launc h of pulses with sufficient power. Also, soliton generation can take place through modulation instability and with the amplification of noise. In this paper we will derive the gain of modulation instability and show soliton evolution through the amplification of a seeded noisy signal, which describes the generation of amplified ultrashort solitons from weak-modulated CW la ser source by normalized numerical simulations. Keywords: Modulation instability, noise ampl ification, optical fiber, soliton 1. INTRODUCTION Optical solitons are ideal signal waveforms for ultrahigh-bitrate long-distance optical communications. 1 Through the past years several techniques for pulse compression and generation of ultrashort soliton train with high quality and repetition rate have been invented. One of them is modulation instability (MI) 2 which results from the combined effects of self phase modulation (SPM) and group velocity dispersion (GVD) in a fiber and implies that an amplitude- and/or phase-modulated continuous wave (CW) optical signal becomes unstable for spontaneous noise frequencies, which contain a broad range up to a few terahertz |
