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Theoretical Study And Experimental Fabrication Of Phase-Sampled Fiber Bragg Grating

Posted on:2006-11-02Degree:MasterType:Thesis
Country:ChinaCandidate:X M XuFull Text:PDF
GTID:2178360182983593Subject:Electronic Science and Technology
Abstract/Summary:PDF Full Text Request
Fiber Bragg grating (FBG) is one of the most important fundamentalcomponents in optical communication and optical sensors system. Recently, thetheoretical and experimental study of phase-sampled FBG has been very popular.Compared with amplitude-sampled FBG, phase-sampled FBG has one moreadjustable factor — grating phase, so the design of phase sampled FBG is moreflexible. The phase-sampled FBG has many new characteristics, so it has morepotential in its future application. By the work of this thesis, the OpticalCommunication Laboratory of Tsinghua University has deeply studiedphase-sampled FBG for the first time. Many achievements about the theory,fabrication and application of phase-sampled FBG have been obtained by the work ofthis thesis.By the theoretical study, phase-sampled FBGs have been classified as two kindsby the sample function: (1) both amplitude and phase sampled FBG, (2) purelyphase-sampled FBG. For both amplitude and phase sampled FBG, many new gratingstructures have been proposed in this thesis. The most important achievement is: byintroducing phase shifts after each sample in the strongly chirped FBG, comb filterswith arbitrary channel spacing can be designed using only a single chirped phasemask. Not only are the structures of these comb filters easy, but also they havepowerful potential in tunable fiber laser. On the other hand, a new arithmetic forpurely phase-sampled FBG has been proposed. Many purely phase-sample gratingstructures with novel spectral characteristics are designed. By the study of grating fabrication, a steady and precise experimental stage forgrating phase shift is set up. Phase shift is made by precisely moving the phase maskduring the process of grating writing. Using this phase shift experimental stage, manycomb filters with different channel spacing are fabricated by using only a single phasemask. This kind of comb filters features in broad bandwidth, large channel spacingand flat top in their reflection spectra.By the study of these FBGs' application, using two phase-sampled comb filterswith different channel spacing as reflectors, a DBR tunable fiber laser with largetunable bandwidth and uniform power response has been set up. By comparing withother FBG fabrication techniques, this kind of phase-sampled FBG shows manyadvantages for tunable fiber laser.
Keywords/Search Tags:fiber Bragg grating, phase sample, phase shift, comb filter, tunable fiber laser
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