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Research On The Theory And Application Of The Novel Fiber Bragg Gratings

Posted on:2007-12-10Degree:DoctorType:Dissertation
Country:ChinaCandidate:Y T DaiFull Text:PDF
GTID:1118360212985339Subject:Electronic Science and Technology
Abstract/Summary:PDF Full Text Request
Fiber Bragg gratings (FBGs) have the potential to realize complicated, frequency-domain optical signal processing as well as broadband, multi- channel filtering and dispersion compensating, and such devices have found many applications in all kinds of optical fiber systems. However, by present technologies, there are many difficulties to fabricate such devices: platforms with nanometer precision control or very expensive phase masks are usually required. This thesis demonstrates a series of innovations in the device structure to solve the above problems.The reconstruction-equivalent-chirp (REC) technique is demonstrated to realize complicated, frequency-domain optical signal processors by only ordinary phase masks and micron or sub-micron precision control. With a specially designed sampling function, one can get the desired frequency response in the -1st-order channel of the sampled Bragg grating (SBG). Compared with others technique (such as the super-structured FBG), there is at least two order of magnitude lower in the precision requirements. The REC technique simplifies the fabrication of complicated FBG, which leads to the low cost and high quality. Based on the REC method, several FBG-based devices have been demonstrated in this thesis, including: (1) tunable dispersion compensator for 40-Gb/s optical fiber communication system; (2) high-order dispersion compensator for pure third-order dispersion and for tunable dispersion slope compensation; (3) 511-chip, 500GChip/s en/decoders for optical CDMA system; and (4) stable, dual-wavelength, narrow- wavelength-spaced DFB fiber lasers. Based on the REC technique, both the simple fabrication and the high performance are achieved.Based on the analysis of all kinds of multi-channel FBG devices, two basic models for multi-channel SBG are proposed in this thesis. The concept of"space-division-multiplex"is then proposed, and phase-shifted, large-chirped SBGs (LCSBGs) are demonstrated and analyzed in detail. By a single phase mask, one could get broadband, multi-channel comb filters as well as dispersion compensator with the desired channel spacing and dispersion value. Compared with other techniques (such as the phase-only sampling technique), the LCSBG is much more flexible and simple to realize. A 100GHz-spaced, 40-channel multi-channel dispersion compensator is experimentally demonstrated, which makes the LCFBG the second technique to realize the broadband (>30nm) multi-channel dispersion compensator, following the phase-only sampling technique.In order to improve the performance of the fabricated SBG devices, the reconstruction is introduced into the fabrication of the SBG for the first time. Reconstruction aiming at a single channel of the SBG is demonstrated. Meanwhile, this thesis proposes a novel method to measure the structure parameters of the SBG by measuring those of the sub-gratings corresponding to each channel. Based on the measured parameter-errors, correction techniques corresponding to REC-based SBG and LCSBG, respectively, are demonstrated. Combined with the error-correction techniques, performances of all the SBG devices fabricated in this thesis are improved greatly.
Keywords/Search Tags:fiber Bragg gratings, reconstruction, frequency-domain optical signal processing, multi-channel, dispersion compensation
PDF Full Text Request
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