窄带太赫兹辐射产生技术研究
文献类型：学位论文
| 作者 | 周萍 |
| 学位类别 | 博士 |
| 答辩日期 | 2011 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 范滇元 |
| 关键词 | 太赫兹辐射，四波混频，表面发射，微波光子学，调制不稳定性 |
| 其他题名 | Research on Narrowband Terahertz Radiation Generation |
| 中文摘要 | 太赫兹辐射是指频率在0.1~10THz之间的电磁辐射，在电磁波谱上处于微波和红外辐射之间。近年来，太赫兹技术受到各国高度重视，太赫兹辐射源更是研究的热点。特别是通信、雷达、遥感等诸多应用领域对窄带（相干）型太赫兹辐射源的需求迫切，要求很高。期望辐射源不仅具有窄带（相干）、可调谐、高功率等优良性能，同时还具有结构紧凑、造价低廉、室温操作等便于应用的特点。 迄今符合要求的辐射源还很少，因此，探索和开发满足应用需求的窄带型太赫兹辐射源，是十分必要和有意义的。 本论文提出并研究了几种有发展前景的辐射源技术途径，包括：基于光纤四波混频机制的太赫兹源技术；基于微波光子学原理产生低端太赫兹辐射技术；以及基于光纤中调制不稳定性产生超高重频脉冲串并解调以产生高端太赫兹辐射的方案。详细分析研究了各方案的原理、机制、技术路线和输出性能，开展了部分实验验证。这些工作取得了一系列创新性研究成果，为窄带辐射源的实用化发展奠定了基础。部分研究成果已在Chinese Optical Letters 等学术刊物发表，SCI收录论文1篇，EI收录3篇，并申请发明专利2项。 论文的主要研究内容有： 1、系统分析和评述了三类产生太赫兹辐射的技术途径（电子学方法、光学方法和光电子学方法）。从工作原理、输出频率范围和功率水平、系统造价、操作复杂程度等几方面，进行了详细的比较研究，为我们提出新的辐射源方案提供基础。 2、提出并研究了基于光纤四波混频效应的窄带太赫兹辐射产生方案。分别针对共线发射和表面发射两种机制进行了详细的理论分析，得到了相位匹配条件以及太赫兹辐射功率的解析表达式。研究表明，共线机制产生的太赫兹辐射易于控制但功率较低（μW量级）；而表面发射机制效率较高，辐射功率可达mW量级。采用高非线性光纤后，可获得更高的输出功率。 3、提出并研究了基于微波光子学技术的窄带太赫兹辐射产生方案。采用微波光子学的光学倍乘技术，实现微波频率的光学二倍频、四倍频以及八倍频，从而能够产生低端太赫兹辐射（0.1~0.2THz，可调谐）；采用掺铒光纤放大器对光载波功率放大，辅以检波后的电功率放大，显著提高了太赫兹辐射功率。成功地进行了实验验证，在二倍频方案中，实验产生了10mW 的60GHz辐射；在四倍频方案中，获得了1mW的100GHz辐射输出。 4、将微波光子学系统进一步向高频端发展，提出了解调高重复频率脉冲串的强度包络以获得1THz以上的高频窄带太赫兹辐射的方案。其中高重复频率脉冲串的产生是整个方案的关键。详细讨论了通过调制不稳定性产生高重复频率脉冲串的原理，分别针对自诱导和SPM引起的调制不稳定性两种机制进行了理论分析和数值模拟。研究表明，光纤中的调制不稳定性是产生可调高重复频率脉冲串的有效方法，而且这种全光纤的系统结构简单、造价低廉，可实现信号的高功率放大和远距离传输，符合当前窄带太赫兹辐射源的性能需求。 |
| 英文摘要 | Terahertz radiation is electromagnetic wave with the oscillation frequency of about 0.1~10THz, which lies in the the frequency gap between the infrared radiation and microwaves. Terahertz technology has attracted a great deal of attention in recent years, and the THz radiation source has become the research focus. Narrowband THz radiation source has been urgently needed for high-speed wireless communication, radar technology and remote sensing, etc. The radiation source is expected to be narrowband, compact, tunable with low cost and high output power at room temperature. There exists few radiation souces which can meet the application requirements. So it is significant to explore narrowband THz radiation source which can satisfy the application demand. This article proposed and studied several promising technical approaches for narrowband THz radiation generation, including the scheme based on four-wave mixing effect in optical fibers, the scheme based on microwave photonics to obtain low-frequency narrowband THz radiation, and the scheme based on demodulation of pulse trains with high repetition rates to obtain high-frequency narrowband THz radiation. The priciples, mechanism, technical approach and output capability have been studied in detail, and experimental demonstration has been finished partly. From this work we attain considerable innovative results which will be a solid foundation for the practical development of narrowband THz radiation source. Parts of our achievements have been published in Chinese Optical Letters and others, among which 1 paper was indexed by SCI, 3 papers indexed by EI, and we applied 2 invention patents. Main contents of this thesis are summarized as follows: 1. We analyzed and reviewed in detail the three kinds of technical approaches to generate THz radiation: electronic methods, optical methods and optoelctronic methods. The comparison research from the priciples, experimental scheme and output power level is a valuable reference for the design of new generation scheme. 2. We proposed and studied the narrowband terahertz generation scheme based on four-wave mixing effect in optical fibers. The theoretical analysis has been made for copropagation and surface-emitting cases. The phase-matching conditions and analytical expression of output power have been derived. The results show that the copropagation scheme can generate THz wave with peak power on the order of μW, and the radiation is easily to be controlled; while surface-emitting scheme can generate THz wave with peak power on the order of mW. Greater output power can be obtained with the highly nonlinear optical fibers. 3. We proposed and studied the narrowband terahertz generation scheme based on microwave photonics. The low frequency narrowband THz signals (0.1~0.2THz, tunable) can be generated through twofold, quadrupling and eight octave frequency multiplication. The THz radiation power has been increased significantly due to the amplification of optical carrier power by EDFA and the amplification of the electrical signal power by power amplifier after the photodetector. We have detected the THz radiation power of 10mW at 60GHz under the twofold frequency multiplication scheme, and 1mW of 100GHz under the fourfold frequency multiplication scheme, as illustrated by our successful experimental demonstration. 4. We proposed a scheme to generate narrowband THz radiation with frequency higher than 1THz by the demodulation of the intensity envelope of pulse train with ultra-high repetition rate, which is the development of the microwave photonic system. The key point of this scheme is to obtain the pulse train with high repetition rate. We gave a detailed discussion about the generation principle of pulse train with high repetition rate based on the modulational instability in optical fibers, and the theoretical analysis and numerical simulation have been presented for self-induced modulational instability and modulational instability induced by SPM. The results show that the modulational instability in optical fibers is an effective way to generate pulse train with high repetition rate. The all-fiber configuration of this schem makes the system compact, low-cost, capable of high output power and long distance transmission, which are quite suitable for current narrowband THz radiation applications. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15664]  |
| 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 | 周萍. 窄带太赫兹辐射产生技术研究[D]. 中国科学院上海光学精密机械研究所. 2011. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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