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The Ultra-short Laser Pulse Shaping Research Based On A Pair Of Chirped Fiber Bragg Gratings

Posted on:2012-06-13Degree:MasterType:Thesis
Country:ChinaCandidate:H P YanFull Text:PDF
GTID:2178330332491080Subject:Circuits and Systems
Abstract/Summary:PDF Full Text Request
With the rapid increase of the communication capacities, the timming jitter become a key problem in high repetition rate optical communication. Flat top pulse shaping technology can greatly decrease error codes due to timming jitter. In this dissertation, flat top pulse shaping system based on a pair of chirped fiber Bragg gratings (CFBGs) is presented and analyzed, which include:1. The ultra-short pulse shaping technology is reviewed:The ultra-short flat pulse shaping technologies based on super-structure fiber Bragg grating, electro-optic crystal, liquid crystal spatial light modulator and nonlinear loop mirror are introduced detailedly2. The transmission characteristics of CFBGs are detailedly studied through the simulation:Reflectivity and delay characteristics of CFBGs are analyzed when changing the length, the chirp coefficient and the depth of refractive index modulation of the CFBGs. The reflectivity and delay characteristics of CFBGs are also analyzed when the two CFBGs are apodized with different apodization functions of higher-order cosine functions, cosine functions and Gaussian function respectively. And it is found in the simulation that a better reflectivity and time delay characteristics can be obtained when adjusting the apodization function, length and chirped coefficient.3. Flat top optical pulse shaping system based on a pair of CFBGs is presented, and corresponding theory analyzation is also given. In the flat top optical pulse shaping system based on a pair of CFBGs, the two CFBGs have the same optical parameters except that the sign of chirp coefficients of the two CFBGs are opposites and the first CFBG is apodized to get reflective spectrum with envelop of sinc function. Thus, the ultra short optical pulse goes into the first CFBG and apodized for the spectrum of output pulse, the chirped output pulse then goes into the second CFBG with opposite chirp coefficient, the chirp of the optical pulse is then compensated and flat top optical pulse can be obtained. In the simulation, we analyze output optical pulse with different spectral width and different input pulse width, it is found that optimized flat top pulse can be obtained when choosing proper width of reflective spectrum.
Keywords/Search Tags:ultra-short optical laser pulse shaping system, CFBG, coupled-mode theory, transfer matrix analysis
PDF Full Text Request
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