窄线宽光纤激光器的研究
文献类型：学位论文
| 作者 | 杨敬 |
| 学位类别 | 硕士 |
| 答辩日期 | 2005 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 瞿荣辉 |
| 关键词 | 光纤激光器 窄线宽 环形谐振腔 可饱和吸收体 |
| 其他题名 | Study on narrow linewidth fiber lasers |
| 中文摘要 | 光纤激光器在光纤通信和光纤传感中有广泛的应用。特别是单频运转的窄线 宽光纤激光器，具有输出功率高·单纵模、线宽比DFB半导体激光器更窄等优点可以作为DwDM系统的光源，同时也是激光分布式传感的理想光源。本文 研究了光纤激光器的一般理论和窄线宽激光器的相关理论，得到了激光器相关参 数对输出特性的影响，以及线形腔实现单纵模运转对激光器相关参数的要求；探 讨了基于光纤光栅FP效应的光纤环形激光器的特性，并提出了性能优化的方法；从理论和实验两方面深入研究了光纤环形谐振腔滤波器和掺饵光纤可饱和吸收 体的机理，实现了一种消除拍频噪声的单模光纤激光器，并对其可调谐特性进行 了初步的实验研究。本文的主要内容包括以下几个方面：本文对光纤激光器的输出特性做了全面的研究，从速率方程出发推导出了泵 浦闽值、输出功率和斜率效率的解析表达式，并对这些特性进行了数值模拟。通 过对模拟结果的分析，发现对于一定的泵浦功率存在一个最优饵纤长度，同时还 模拟了不同的输出祸合比对输出功率的影响，这对光纤激光器的设计具有一定的 指导意义。除了研究光纤激光器的一般理论，还讨论了线形腔单模运转理论，该 理论指出，当线形腔内的增益和损耗满足特定条件时，就可以克服伴随线形腔的 空间烧孔效应从而实现单纵模振荡。本文探讨了用FBG构成FP滤波器，实现可调谐单纵模光纤激光器的可行性。 特别是利用取样光纤光栅的游标效应，可以比较容易地实现宽范围的调谐。文中 讨论了当两光栅的反射谱峰值波长不一致时FP峰值透过率的变化，以及对激光 器输出特性的影响。数值计算的结果表明，光纤光栅的不稳定性和FP腔的附加 损耗大大提高了获得稳定的单纵模输出的难度。实验结果很清楚地说明了这一 点。可饱和吸收体和光纤环形谐振腔滤波器是两种优良特性的滤波器。文中详尽 地讨论了可饱和吸收的机理，用数值计算模拟了可饱和吸收效应，并通过饵纤对 1550nm不同强度的激光的吸收实验，验证了我们的理论。文中进一步分析了当 驻波存在于可饱和吸收体上时所体现出的滤波器效应，并用数值计算模拟了这种 效应。文中还讨论了光纤环形谐振腔滤波器的基本原理，设计制作了一个这样的 滤波器，通过测量它对ASE光滤波所形成的拍频，间接测量了它的自由谱区。利用可饱和吸收体和光纤环形谐振腔滤波器，将它们结合光纤光栅的可调谐 特性，实现了一种消除拍频噪声的单纵模光纤激光器，并进行了调谐性能的实验 工作。实验发现，若仅仅使用FBG作为滤波器，则会出现频繁的多模振荡，并且有很强的拍频噪声；光纤环形谐振腔滤波器可以很有效的抑制ASE，从而消 除拍频噪声，但仍然伴随多模振荡；若仅使用可饱和吸收体，发现拍频噪声仍然 存在，只能够在较短时间内维持单纵模，这是可饱和吸收的强度不够所致：当同 时使用了光纤环形谐振腔滤波器和可饱和吸收体以后，获得了稳定的消除拍频噪 声的单纵模输出，并用零拍法测量得到输出激光的线宽小于5kHz。基于这种结构，又进一步做了可调谐光纤激光器的实验工作，分别用级联可调谐光纤光栅和可调谐滤波器实现了超过35nm的稳定调谐输出。 |
| 英文摘要 | Fiber lasers have wide application in optical fiber communication and optical fiber sensing systems. The narrow linewidth fiber laser is the ideal light source for DWDM systems and distributed fiber sensing systems, due to its high output power, single longitudinal mode (SLM) operation and narrower linewidth than DFB semiconductor laser, etc. In this dissertation, the general theory of fiber laser and specific issues of narrow line-width fiber laser are discussed in detail. Influence of some parameters on output characteristics is presented, as well as the requirement for the linear cavity fiber laser to be operated in SLM. A fiber ring laser is demonstrated by utilizing FBG based FP filters, performance optimization scheme is also proposed. Based on theoretical and experimental studies on optical fiber ring resonator and erbium-doped fiber saturable absorber, a fiber ring laser is realized to obtain the SLM output without beat noise. The tuning ability of this SLM fiber ring laser is investigated experimentally. The main contents of this thesis are as follows: Using rate equations, the analytical solution of output characteristics is developed, including pump threshold, output power and slope efficiency. From the result of numerical simulations, it's found that an optimized length of erbium-doped fiber exists for a certain pump power. The relation between output power and output-coupling ratio is also studied. The theory of linear cavity SLM fiber laser is also deduced. It is illustrated that spatial hole burning in linear cavity can be overcome if some special requirements are satisfied, so SLM operation would be obtained. Feasibility of a fiber ring laser based on FBG based FP filters is studied. By utilizing the vernier effect of sampled fiber Bragg gratings with slightly different reflection spectrum periods, a widely tunable FP can be realized. The characteristics of FP filter that is composed of two FBG with slightly different reflection peaks are analyzed, as well as the influence on the laser output characteristics. Simulations show that difficulties will be extremely induced by the instability of FBG and extra loss of FP resonator. It is proved clearly by experimental results. Fiber ring resonator and saturable absorber are two kinds of filters with good performance. The theory of saturable absorption is developed, and absorptions of Erbium doped fiber at 1550nm are measured, which agrees well with the theory. The filtering effect of saturable absorber with standing wave is further discussed and simulated. Basic principle of fiber ring resonator is also analyzed, and one fiber ring resonator is designed and produced. FSR is obtained indirectly by measuring the beat signal of filtered ASE signals. Utilizing saturable absorber and fiber ring resonator filter, the SLM fiber ring laser without beat noise is realized. Furthermore, the tuning ability is studied experimentally based on fiber Bragg grating. It is illustrated in the experiments that: multi-mode operation with strong beat noise can be obtained only using FBG as a filter; beat noise can be suppressed well by using fiber ring resonator; SLM operation with beat noise could be realized unstably if only saturable absorber is used, since the intensity of saturable absorption is not strong enough. Combining the fiber ring resonator and saturable absorber, stable SLM operation without beat noise is obtained eventually, which linewidth is narrower than 5kHz measured by self-heterodyne method. Based on this structure two tunable fiber ring lasers with stable operation are realized, and tunable range is over 35nm. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/16508]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 杨敬. 窄线宽光纤激光器的研究[D]. 中国科学院上海光学精密机械研究所. 2005. |
入库方式： OAI收割
来源：上海光学精密机械研究所
浏览0
下载0
收藏0
其他版本
除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。