空心布拉格光纤是具有一维光子晶体(1DPC)包层和空心芯区的新型光子带隙光纤。针对它在CO2激光传输中的应用，设计和制备了传输波段中心波长在10.6 μm的空心布拉格光纤样品。利用傅里叶变换红外光谱仪(FTIR)可以观察到光纤样品在10.6 μm具有明显的透射峰。使用CO2激光，通过截断法测量得到光纤样品在10.6 μm的传输损耗为2.35 dB/m。测量了不同弯曲曲率下光纤样品的弯曲损耗，结果表明弯曲损耗系数随曲率的增大而线性增长。在接近光纤输出端处，弯曲半径为10 cm的光纤90°弯曲引入的附加损耗约为2 dB。实验结果论证了光纤样品的CO2激光低损耗传输特性，展现了空心布拉格光纤在提升CO2激光操作灵活性上的应用潜力。

利用基于非对称的马赫曾德尔干涉仪(UMZI)的异质光纤环腔实现了双向双波长多模布里渊激光，激射光与抽运光拍频的中心频率分别约为10.49 GHz和10.54 GHz。实验测量了该结构在不同转速下双向斯托克斯光拍频中纵模的频移量。实验结果表明，频移量随转速线性变化，在实验测量范围内没有观察到闭锁效应，且根据环腔转动时拍频信号频率相对于环腔静止时拍频的频移可以明确判断环腔转动方向，提供了一种实现布里渊光纤陀螺(BFOG)的新思路。实验测得陀螺效应标度为1.0305 kHz/(°·s-1)，与理论分析吻合较好。

在空心布拉格光纤拉制过程中引入的光纤外径波动会造成不同位置光纤包层一维光子晶体结构的光子带隙不完全重叠，极大地影响光纤的传输特性。研究了外径慢变正弦波动下，空心布拉格光纤中各类模式的传输特性。理论计算表明，尽管各模式类传输特性不尽相同，同一类模式中，不同阶的模式损耗情况也不一样，但是，各模式的外径波动容限相差不大。在计算例中，TE0n模的外径波动容限大约为9％，TM0n，HE和EH模式的外径波动容限在6％～7％。采用的理论分析方法可以拓展到其他光纤结构参数组合和任意光纤波动情况。

Two-dimensional (2D) slab photonic crystal waveguides (PCWGs) on silicon-on-insulator (SOI) wafer were designed and fabricated. Full photonic band gap, band gap guided mode, and index guided mode were observed by measuring the transmission spectra. Mini-stop-bands in the PCWG were simulated with different structure parameters. Coupling characteristics of PCWG were investigated theoretically considering the imperfections during the fabrication process. It was found that suppressing power reservation effect can realize both short coupling length and high coupling efficiency.

针对长跨距密集波分复用系统中喇曼放大入纤泵浦功率过大的问题，将遥泵放大器(RPEDFA)引入到系统中，通过对共纤RP－EDFA的噪音性能及其优化设计的研究，在理论上计算比较了RP－EDFA系统和后向喇曼放大系统在不同泵浦功率水平下的光信噪比和非线性相移，表明遥泵放大技术有效降低了入纤泵浦的功率水平，更适合长跨距应用．运用遥泵放大技术，对一个典型的长跨距系统进行系统Q值的模拟，结果表明：在220mW泵浦功率水平下可以实现跨距为167km的40×11．6 Gbit／s系统1000 km传输，Q值裕量4．4 dB．

The 1.3-um polarization-insensitive superluminescent diodes (SLDs) with weak tensile strained multiple-quantum-well (MQW) and complex strained MQW were demonstrated theoretically based on the simulation of energy band structure and gain spectra at different injected carrier densities. Compared with the weak tensile strained MQW, the complex strained MQW gets higher modal gain and better modal gain matching between TE and TM modes, and the polarization sensitivity of TE and TM optical spectra can remain less than 1.0 dB over a bandwidth of 200 nm.

In this paper, aiming at practical dense wavelength division multiplexing (DWDM) system with ultra-long fiber span, a simple co-fiber remotely pumped erbium-doped fiber amplifier (RP-EDFA) scheme is proposed to extend span distance with simple configuration and low pump power. Equivalent noise figure of -6 dB is achieved under 300-mW pump power. Using the experiment results, numerical simulation of ultra-long span systems shows that for a 40*11.6-Gb/s transmission system, the RP-EDFA scheme can support transmission of 1760 km with a fiber span of 160 km. These results demonstrate the potential of the PR-EDFA scheme in ultra-long span transmission.

A broadband multiwavelength Raman fiber ring laser (RFRL) covering the whole C-band at room temperature are presented. The effect of the intracavity highly nonlinear dispersion-shifted fiber on broadening and flattening the output spectrum envelope is discussed and experimentally demonstrated. More than 45-dB extinction-ratio multiwavelength output from 1527.76 to 1566.86 nm with 100-GHz channel spacing and 2.1-dB power ripple has been achieved by carefully controlling the individual powers of three pump lasers.

The characteristics of broadband backward and bi-directionally pumped distributed fiber Raman amplifiers (DFRAs) in hybrid Raman/erbium-doped fiber amplifiers (HFAs) configuration are compared numerically based on noise-nonlinear figure (NNF) when standard single mode fiber (SMF) and non-zero dispersion-shifted fiber (NZDSF) are considered. It is found that achievable NNF in optimized bi-directionally pumped HFAs is about 1.2 dB (or 1.7 dB) higher than that in backward pumped HFAs for SMF (or NZDSF), and better characteristics can be achieved by using NZDSF rather than SMF for long haul transmission.

Output power spectrum clamping over C+L band (84 channels) is demonstrated experimentally on a standard 100-km single mode backward-pumped distributed fiber Raman amplifier (B-DFRA). The clamping is realized by pump adjustment based on a simple linear relation of individual pump power versus on-off gain level and gain tilt in its spectrum. The average clamping error over all channels are less than 0.32 dB within the experimental range.