单频光纤激光器研究
文献类型：学位论文
| 作者 | 潘政清 |
| 学位类别 | 博士 |
| 答辩日期 | 2009 |
| 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 | 单频 光纤激光器 磷酸盐玻璃光纤 SBS 调Q 毫米波光脉冲 |
| 其他题名 | study on single-frequency fiber laser |
| 中文摘要 | 单频光纤激光器在激光雷达、相干通信、远距离传感、原子频标等领域具有 广泛的应用，成为近年来研究的热点。在光纤激光器单频技术中，短腔结构最容 易实现，但它也在一定程度上限制了激光器输出功率的提高。高掺杂磷酸盐玻璃 光纤的引入克服了短腔激光器低功率输出的问题。由于具有比石英光纤更高的掺 杂浓度，因而更容易实现高的泵浦吸收和增益，获得更高的能量输出。单频铒镱 共掺磷酸盐玻璃光纤激光器在过去几年取得了迅速发展，实现了更高的输出功 率，更窄的线宽。本文在这一研究背景下开展工作，具体研究内容包括以下几方 面： ■利用国产磷酸盐玻璃光纤作为增益介质，实现了厘米量级激光腔长的高功 率单纵模激光输出，最大输出功率达到100mW，斜率效率为24％。同时实验结 果也证实了激光器的单纵模（输出线宽为4.5kHz）运转特性。 ■观察到了该激光器外部盘绕光纤诱发的不稳定现象：即高频调制，混沌和 自脉冲。文中通过将扭转外部光纤等效为椭圆延迟器，并结合微弱的外部反馈对 此现象给出了合理的解释。 ■采用偏振选择反馈方法实现了激光器的单偏振运转。该方法利用一偏振分 束器作为激光器输出端，光纤端面4%菲涅耳反射提供反馈，抑制某一偏振态起 振。实验结果显示激光器输出很好的线偏光，输出偏振消光比>35dB，线宽进一 步降低至2kHz。 ■针对低阈值受激布里渊（SBS）调Q 光纤激光器具有重复频率不稳定的缺 点，我们提出了一种通过注入矩形波调制光稳定重复频率的方法，实验结果显示 不稳定度由20％下降至1％。文中还详细研究了调制频率和占空比对稳定效果的 影响，并且利用数值方法对工作机理进行了定性分析。 ■提出了一种结合光时分复用(OTDM)技术和Talbot 效应产生毫米波光脉冲 的方案。使用级联马赫－曾德干涉仪制作OTDM，线性啁啾光纤光栅产生Talbot 效应，借助高斯注入脉冲进行理论分析，采用数值模拟讨论其工作性能。结果显 示了该方案在毫米波产生和ROF 实际应用中的可行性。 |
| 英文摘要 | Single-frequency fiber laser has become a research hot topic in the last decade for its widespread application in lidar, coherent communication, remote sensing, atom frequency standard, etc. Among the single-frequency technologies in fiber laser, the structure of short linear cavity is the simplest method, which however limits the output power substantially. The introduction of phosphate glass fiber overcomes the problem of low power in short linear laser because of much larger doping concentration than silicon fiber. Thus it has much higher pump absorption and gain coefficient. The single-frequency Er/Yb co-doped phosphate fiber laser has gained great development in the last several years, achieving higher output power, narrower linewidth and larger tuning range. The research was done in such background, and the main contents of the thesis are as follows: We demonstrated a high power single-longitudinal-mode fiber laser by using homemade phosphate glass fiber as its gain media. The laser can achieves high output power of 100 mW and slope efficiency of 24% in centimeter long linear cavity. Single longitudinal-mode operation with 4.5 kHz linewidth is verified. Three typical instability cases in fiber laser were observed when swirling the outer fiber, including high frequency intensity fluctuation, chaos and self pulsing. Reasonable explanation was proposed by considering the swirled fiber as ellipse delayer and combining tiny external feedback. The single polarization operation in fiber laser is achieved by using a polarization selective feedback method. It is based on a polarizing beam splitter (PBS) which is added to the output port of the laser and the feedback is provided by 4% facet Fresnel reflection. One of the polarization modes is prohibited from lasing. The experiment demonstrated good linear polarization characteristics of our fiber laser with>35dB PER and 2 kHz linewidth. Repetition rate fluctuation is one of the main drawbacks of the low-threshold stimulated Brillouin scattering (SBS) Q-switched fiber laser. A method to stabilize the repetition rate is proposed by injecting a square-wave modulated light. It is measured experimentally that variance of the repetition rate can be improved from ~20% to ~1% of the period. It is also found that effectiveness of the method depends on modulation frequency and duty cycle of the injection. Its working mechanism is analyzed qualitatively. A novel scheme is proposed to generate a millimeter-wave (MMW) optical pulse by combining Optical Time Division Multiplexing (OTDM) technology and temporal Talbot effect (TTE). A cascaded Mach-Zehnder interferometer (MZI) lattice is used for OTDM, and an Linearly Chirped Fiber Grating (LCFG) plays a role of TTE. The basic principle is analyzed by using a Gaussian input short pulse, and its characteristics are discussed by numerical simulation. It is shown that the proposed scheme is feasible for MMW signal generation and has potential merits for practical application of Radio over Fiber (ROF) technology. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15288]  |
| 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 | 潘政清. 单频光纤激光器研究[D]. 中国科学院上海光学精密机械研究所. 2009. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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