为了减少测试过程中人为因素引起的误差，提高掺铒光纤放大器（EDFA）的测试质量和效率，文章基于python语言设计了能快速测试EDFA瞬态的自动测试系统。根据EDFA的工作原理和速率方程，联系光纤通信过程中产生瞬态的原因设计了合理的测试方法。利用接口总线实现了该系统可由一台计算机同时控制多台测试仪器，并且通过python语言实现仪器设备的自动化控制和“一键式”自动保存各个仪器设备的测试数据和图形。实验结果表明，该系统测试精度较高，操作方便，可扩展性好，能够充分满足用户对瞬态测试的要求。

针对现有的光时域反射仪(OTDR)在监测带有掺铒光纤放大器(EDFA)的长途多跨段光纤链路时, 为克服EDFA增益的波动需增加一个额外的补光来保持功率稳定的问题, 文章基于线性调频OTDR提出了一种无需补光穿越EDFA的长途多跨段光纤监测技术。该技术利用线性调频准连续光作为探测光, 可以避免EDFA增益的波动。同时通过分数域傅里叶滤波来去除级联EDFA累积的自发辐射白噪声, 从而提高接收信号的信噪比。实验结果表明, 该技术能够准确地测出中长途多跨段光纤链路中EDFA和连接点处的反射事件。

光纤放大器作为分布式光纤传感系统实现超长距离、超低损耗传输必不可少的光学器件, 其噪声特性对于系统整体性能有着至关重要的影响。微分干涉型分布式光纤传感系统中必须使用宽谱光源, 同时探测终端也需采用宽谱探测, 因此研究EDFA在宽光谱系统中的噪声对于传感系统整体性能的提升有着重要意义。文中研究了EDFA增益对宽谱光源波长与功率的响应关系, 得出了可描述这一关系的增益响应曲线, 并依此提出了一种可表征EDFA放大宽谱光源的噪声的估测方法, 总结了EDFA放大宽谱光源时的噪声规律。

为了解决光纤多普勒测振仪远距离非接触测量物体振动时，信号偏弱、过零点波形凌乱、难于解调的问题，本文提出了一种新型光纤准直系统。本系统主要采用在小型C-lens光纤准直器后端增加整形系统并借助ZEMAX软件对高斯光束进行准直并优化，通过对光纤准直系统成品进行耦合测试实验，使用C-lens准直器与光纤准直系统进行信号耦合效率的测试对比。实验结果表明：改进后的准直系统能够满足2 m的工作距离，空间返回光耦合效率最大能达到6.3%，极大地提升了多普勒信号的对比度，提高了远距离光纤多普勒测振仪对振动的测量精度。

针对传统偏振测量较难同时实现高灵敏度和较好稳定性的问题，提出了一种采用光纤环形腔衰荡光谱技术进行偏振测量的方法，并进行了实验证明.对比分析了掺铒光纤放大器放置在环形腔的内部和外部对脉冲曲线和脉冲数量的影响.在掺铒光纤放大器中使用长度为2 m的低增益和低噪声掺铒光纤来减少波形失真并补偿环形腔的内部衰减.利用光纤环形腔衰荡光谱系统对偏振角进行测量，通过记录分析环形腔中光脉冲的衰减时间得到偏振角的变化.结果表明：偏振角和衰减时间在0°~90°的范围内满足良好的线性关系，光纤环形腔衰荡光谱系统的灵敏度和拟合曲线的相关系数分别为4.05 μs/°和0.999 6，最大灵敏度误差为0.027 3 μs/°.通过10次重复实验，选取六组数据进行拟合得到系统的平均再现性误差为0.030 8，重复性良好，可用于旋光溶液测量，也为光纤径向应力双折射特性和光纤激光器的偏振态测量提供了参考.

基于EDFA的理论模型和受激拉曼散射效应的分析理论, 利用EDFA和RFA的增益谱互补特性, 对拉曼光纤放大器(RFA)采用两根光纤级联方式, 研究并设计了EDFA与级联光纤的RFA相结合的混合放大器结构。仿真结果表明: 在不使用增益均衡器的条件下, 所设计的混合光纤放大器在输出端得到了近似相等的输出光功率, 得到了增益平坦度为0.62 dB、波长带宽为70 nm(1 550~1 620 nm)的结果, 在密集波分复用光通信系统中有重要的应用价值。

Free space optical communication is a line-of-sight (LOS) technology that uses lasers to provide optical bandwidth connections. Potential disturbance arising from the weather condition is one of the most effective factors that influence the bi-directional free space optics (FSO) performance. The complex weather condition in the Middle East region and Arabian Gulf has been dominated by dust storms activities. Dust storms directly affect the characteristics of FSO and consequently lead to an increase in the bit error rate (BER) and deterioration Q-factor to bad levels due to the high attenuation factor. In this research, the authors compare the differences between two bi-directional FSOs. One is the traditional link, and the other has been developed to enhance the system performance under the dust storms condition. The proposed design consists of dual FSO channels, and each one includes erbium-doped fiber amplifier (EDFA) optical amplifiers. This design has demonstrated the proficiency in addressing the attenuation that occurs due to weather stickers. The results prove there is an improvement in performance by measuring the Q-factor. In addition, BER can be significantly improved, and further communicating distance can be achieved by utilizing 1550 nm with multiple channels and EDFA.

The effect of an erbium-doped fiber amplifier (EDFA) placed inside the fiber ring of a cavity ring down (CRD) configuration is studied. The limitations and advantages of this configuration are discussed, and the study of the ring-down time as a function of the current applied and gain to the EDFA is also presented. In this case, the power fluctuations in the output signal are strongly dependent on the cavity ring-down time with the EDFA gain.

A new type of gain flattening filter for amplified spontaneous emission (ASE) source based on erbium doped fiber (EDF) is proposed and demonstrated by fabricating and writing two series ultra-long period fiber grating (ULPFG) on single mode fiber (SMF-28). The novelty method in this research is based on writing the two ULPFGs as fat gratings. The LPG is written by a simple and available arc-discharge method. The pump power based on single-pass backward pump configuration is around 100 mW, and the average wavelength is near to 974 nm. The gain flattening profile is obtained by 3.4 (±1.7) dB ripple in the wavelength range between 1524 nm and 1565 nm with 41-nm band width.

为了获得具有高增益、低噪声和增益平坦度良好等特性的宽带混合放大器, 分别采用EDFA (掺铒光纤放大器)与FRA (光纤拉曼放大器)理论模型, 设计了EDFA+FRA HFA(混合放大器)的结构, 搭建了HFA系统, 优化了HFA性能参数, 研究了HFA的增益、带宽、平坦度和噪声指数等重要性能。通过FRA增益斜率与EDFA增益斜率进行互补, HFA的各项性能指标集中了EDFA和FRA的优点, 弥补了各自的不足, 这对高速率、大容量和宽带宽的长距离光纤通信具有重要意义。