具有任意的频域信号处理能力，以及具有宽带多信道滤波、多信道色散补偿的能力，是光纤Bragg光栅（FBG）发展的趋势。针对现有的FBG的制作技术在上述两个领域内的困难，本论文提出了利用结构创新来简化工艺、从而推动应用的新思路。本论文提出了重构－等效啁啾（REC）理论，利用对采样函数的调制实现对FBG的任意调制，在采样Bragg光栅（SBG）的-1级反射峰内实现任意给定的目标反射响应。制作相同的器件（针对含相移的复杂功能FBG而言），其对制作平台的精度要求（微米或亚微米）比已有技术至少要低两个数量级，从而大大简化了FBG的制作，降低了成本。利用REC方法和传统的制作平台，本论文实现了多种FBG器件，包括：用于40Gb/s通信系统的可调谐色散补偿器，高阶色散补偿（包括纯三阶色散补偿和可调谐色散斜率补偿），用于DS－OCDMA系统的、511码片、500GChip/s的编解码器，以及室温下稳定激射的窄间隔双波长DFB激光器。这些器件都具有更好的性能和更简单的制作工艺。本论文分析了已有的各种多信道SBG技术，总结提出两种基于SBG的多信道结构。在这个基础上，本论文提出了含相移的采样大啁啾Bragg光栅（LCSBG），提出了“空间复用”的概念，并对该结构的原理和设计思路做了全面的讨论。和已有的宽带多信道FBG技术相比，该结构具有灵活性（基于同一相位模板，可以在一定范围内实现具有任意信道间隔和任意色散值的多信道器件）和易实现性（无需特殊的相位模板）。基于该结构，本论文实现了100GHz信道间隔、40信道的多信道色散补偿器，成为继相位采样技术之后第二个实现覆盖30纳米以上的宽带宽多信道色散补偿FBG技术。本论文将重构的思想引入到SBG的制作过程中来，提出了基于重构的SBG制作误差补偿的工艺流程。本论文提出了基于单个反射峰的重构技术，以及利用子FBG的结构推断SBG结构参数的新思路，解决了将重构直接应用于SBG的困难。结合该修正方法，本论文所涉及的SBG器件的性能都有明显的改善。
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.
