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Research On The Amplification Of Ultrabroad Bandwidth Laser Pulse In Fiber Amplifier

Posted on:2007-03-04Degree:MasterType:Thesis
Country:ChinaCandidate:D J LeiFull Text:PDF
GTID:2178360185465285Subject:Computer application technology
Abstract/Summary:PDF Full Text Request
Fiber amplifiers are widely used for pulse amplification owing to their intrinsically robust, good coupling efficiency, high reliability and compactness. The desirability of high-capacity, long-distance, all-optical communication systems and ultrafast lasers have motivated extensively studies of the ultrabroad bandwidth pulse amplification. The ultrabroadband laser is the trend of high power lasers. As the pulse grows shorter, the spectrum becomes broader, and is greatly broaden by the versatile nonlinear effects in fiber amplifier. Under such situation, the effect of gain bandwidth and inhomogeneous broadening for the amplification of ultrabroad bandwidth pulse in fiber amplifier becomes important. Therefore, the exploration and investigation on the amplification of ultrabroad bandwidth pulse in fiber amplifier is of great importance and essential. The main research results are listed below:Firstly, an extended version of the nonlinear Schr?dinger equation which describes the amplification of ultrabroadband pulse is derived. The existing Ginzburg-Landau model is valid only when the amplifier gain bandwidth is significantly larger than the signal's spectral bandwidth. Since the equation that we work out does not assume that the pulse's spectral width remains small in comparison with the gain bandwidth, it can be used to describe the ultrabroad bandwidth pulse amplification. In addition, we have independently developed the computer program which simulates the process of broadband pulse amplification based on the amplification equation of ultrabroadband pulse.Secondly, on the basis of the amplification equation of ultrabroadband pulse, the amplification of chirped-free or chirped pulse with ultrabroad bandwidth in the fiber amplifier is considered by the means of split-step Fourier method. Also, the effect of the gain bandwidth of the amplifier is analyzed. The effects of the relation between the bandwidth of the pulse and the gain bandwidth of amplifier in amplification are studied numerically. The results show that when the gain bandwidth of fiber amplifier is comparable to the bandwidth of pulse, it plays an important role in determining the final spectrum shape. And when the gain is large enough, the supercontinuum comes into being.Thirdly, according to the characteristics of linearly chirped pulse, the input chirped pulses are considered to consist of many quasi monochromatic pulses with...
Keywords/Search Tags:fiber amplifier, broadband laser pulse, gain bandwidth, inhomogeneously broadening, chirped-pulse-amplification
PDF Full Text Request
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