功率均衡度可调谐的双频微腔激光器研究
发布时间：2018-10-21 20:14
【摘要】：相干波源在无线通信、材料光谱分析、频率计量和混合光载波雷达等领域展现了不可忽视的应用潜力。将射频频差的双频激光器的输出信号通过单行载流子光电二极管等外差拍频是产生高纯度射频信号的有效手段。用于外差拍频的双频激光信号的两个频率成分的功率均衡程度直接影响拍频效率。本文提出了一种基于热致双频激光波长和增益介质发射谱漂移的功率均衡度可调谐的双频微腔激光器。首先基于四能级速率方程理论,建立洛伦茨线型的耦合速率方程模型对双频激光信号运行机制进行分析,从理论上揭示造成均匀加宽双频激光器输出功率非均衡的主要原因是双频波长在增益介质发射谱内对应的发射截面不同(即非均衡增益)。更重要的是,温度对双频功率均衡度的影响是双频激光波长和增益介质发射截面谱的温度依赖性共同作用的结果。采用掺杂浓度和外形尺寸均相同的未镀膜的薄片Nd:YVO4晶体和双端镀膜的薄片Nd:YVO4晶体(微腔),分别对不同温控条件下未镀膜薄片Nd:YVO4晶体的发射截面谱和双频Nd:YVO4微腔激光器的输出激光光谱进行研究,从实验上揭示增益介质发射截面谱和双频激光波长随温度变化的一般规律。实验结果表明:在所研究的温控范围内,随着热沉温度的增加,双频Nd:YVO4微腔激光器的输出激光光谱红移,输出功率下降,并伴随有“跳模”现象发生;未镀膜薄片Nd:YVO4晶体的发射截面谱红移,峰值发射截面减小,谱线展宽。双频Nd:YVO4微腔激光器的输出激光光谱包络中心波长,以及未镀膜薄片Nd:YVO4晶体的发射截面谱峰值波长的红移速率分别为3.88 pm/°C和3.84 pm/°C。为了分析双频激光信号的相对强度比变化的原理,对双频激光波长、增益介质发射截面谱,以及它们对输出功率均衡度的相互作用之间的关系进行综合讨论。通过对比上述两条拟合温度特性曲线,发现当激光光谱包络中心波长和发射截面谱峰值波长重合时,双频Nd:YVO4微腔激光器工作温度和未镀膜薄片Nd:YVO4晶体发光区域温度之间存在一个由抽运功率和激光功率的差别引起的温度差。对于本文实验中所涉及到的双频Nd:YVO4微腔激光器,这一温度差近似等于激光增益介质发光区域和热沉的温差,约为54°C。双频激光平均波长与经温度补偿的未镀膜薄片Nd:YVO4晶体的发射谱峰值波长的相对位置决定了双频激光信号的相对功率比。通过精确控制热沉温度,对双频激光波长和增益介质发射截面谱的匹配程度进行调节,实现双频激光输出功率均衡。控制热沉温度在-5.6°C,实验获得功率均衡度约为0.991,输出功率约为264 mW,频差约为67 GHz的双频激光信号输出。在一系列能够达到功率均衡的特定温度点中,较低的热沉温度可以实现更高功率的功率均衡双频信号输出。
[Abstract]:Coherent wave sources have shown great potential in wireless communication, material spectrum analysis, frequency measurement and hybrid optical carrier radar. It is an effective method to produce high purity RF signal by passing the output signal of dual-frequency laser with frequency difference through the heterodyne beat frequency such as single-line carrier photodiode. The power equalization of the two frequency components of the dual frequency laser signal for heterodyne beat frequency directly affects the beat efficiency. In this paper, a dual-frequency micro-cavity laser with tunable power balance based on the wavelength and gain emission spectrum drift of a thermally induced dual-frequency laser is proposed. Firstly, based on the four-level rate equation theory, a Lorentz linear coupling rate equation model is established to analyze the operating mechanism of dual-frequency laser signal. It is theoretically revealed that the main reason for the unbalanced output power of the uniformly widened dual-frequency laser is that the emission cross-sections of the dual-frequency wavelength in the gain medium emission spectrum are different (that is, the unbalanced gain). More importantly, the effect of temperature on dual-frequency power equalization is the result of the temperature dependence of the wavelength of dual-frequency laser and the spectrum of gain medium emission cross section. The emission cross-sections and dual-frequency Nd:YVO4 micro-cavity excitations of uncoated Nd:YVO4 crystals and double-ended Nd:YVO4 crystals (microcavities) with the same doping concentration and shape were investigated under different temperature control conditions, respectively. The output laser spectrum of the optical device is studied. The general rules of the gain medium emission cross section spectrum and the wavelength of dual-frequency laser with temperature are revealed experimentally. The experimental results show that with the increase of heat sink temperature, the output spectrum of dual-frequency Nd:YVO4 micro-cavity laser is red-shifted, the output power is decreased, and the phenomenon of "mode hopping" occurs. The emission cross section of uncoated Nd:YVO4 crystal is red-shifted, the peak emission cross section is decreased, and the spectrum line is widened. The red shift rates of the central wavelength of the output laser spectrum and the peak wavelength of the emission cross section of the uncoated Nd:YVO4 crystal are 3.88 pm/ 掳C and 3.84 pm/ 掳C, respectively. In order to analyze the principle of the variation of the relative intensity ratio of the dual-frequency laser signal, the relationship between the wavelength of the dual-frequency laser, the gain medium emission cross-section spectrum and the interaction between them to the output power equalization is discussed synthetically. By comparing the above two fitting temperature characteristic curves, it is found that when the central wavelength of the laser spectrum envelope and the peak wavelength of the emission cross section spectrum coincide, There is a temperature difference between the operating temperature of dual-frequency Nd:YVO4 microcavity laser and the luminescent region temperature of uncoated thin Nd:YVO4 crystal due to the difference between pump power and laser power. For the dual-frequency Nd:YVO4 microcavity laser in this paper, the temperature difference is approximately equal to the temperature difference between the laser gain medium luminescence region and the heat sink, which is about 54 掳C. The relative position of the average wavelength of dual-frequency laser and the peak wavelength of emission spectrum of uncoated thin Nd:YVO4 crystal determined the relative power ratio of dual-frequency laser signal. By controlling the heat sink temperature accurately, the matching degree between the wavelength of dual-frequency laser and the spectrum of gain medium emission cross section is adjusted to realize the output power equalization of dual-frequency laser. When the heat sink temperature is -5.6 掳C, the power equalization is about 0.991.The output power is about 264 mW, and the frequency difference is about 67 GHz. In a series of specific temperature points which can achieve power equalization, the lower heat sink temperature can achieve higher power equalization dual-frequency signal output.
【学位授予单位】：杭州电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN248
本文编号：2286241
[Abstract]:Coherent wave sources have shown great potential in wireless communication, material spectrum analysis, frequency measurement and hybrid optical carrier radar. It is an effective method to produce high purity RF signal by passing the output signal of dual-frequency laser with frequency difference through the heterodyne beat frequency such as single-line carrier photodiode. The power equalization of the two frequency components of the dual frequency laser signal for heterodyne beat frequency directly affects the beat efficiency. In this paper, a dual-frequency micro-cavity laser with tunable power balance based on the wavelength and gain emission spectrum drift of a thermally induced dual-frequency laser is proposed. Firstly, based on the four-level rate equation theory, a Lorentz linear coupling rate equation model is established to analyze the operating mechanism of dual-frequency laser signal. It is theoretically revealed that the main reason for the unbalanced output power of the uniformly widened dual-frequency laser is that the emission cross-sections of the dual-frequency wavelength in the gain medium emission spectrum are different (that is, the unbalanced gain). More importantly, the effect of temperature on dual-frequency power equalization is the result of the temperature dependence of the wavelength of dual-frequency laser and the spectrum of gain medium emission cross section. The emission cross-sections and dual-frequency Nd:YVO4 micro-cavity excitations of uncoated Nd:YVO4 crystals and double-ended Nd:YVO4 crystals (microcavities) with the same doping concentration and shape were investigated under different temperature control conditions, respectively. The output laser spectrum of the optical device is studied. The general rules of the gain medium emission cross section spectrum and the wavelength of dual-frequency laser with temperature are revealed experimentally. The experimental results show that with the increase of heat sink temperature, the output spectrum of dual-frequency Nd:YVO4 micro-cavity laser is red-shifted, the output power is decreased, and the phenomenon of "mode hopping" occurs. The emission cross section of uncoated Nd:YVO4 crystal is red-shifted, the peak emission cross section is decreased, and the spectrum line is widened. The red shift rates of the central wavelength of the output laser spectrum and the peak wavelength of the emission cross section of the uncoated Nd:YVO4 crystal are 3.88 pm/ 掳C and 3.84 pm/ 掳C, respectively. In order to analyze the principle of the variation of the relative intensity ratio of the dual-frequency laser signal, the relationship between the wavelength of the dual-frequency laser, the gain medium emission cross-section spectrum and the interaction between them to the output power equalization is discussed synthetically. By comparing the above two fitting temperature characteristic curves, it is found that when the central wavelength of the laser spectrum envelope and the peak wavelength of the emission cross section spectrum coincide, There is a temperature difference between the operating temperature of dual-frequency Nd:YVO4 microcavity laser and the luminescent region temperature of uncoated thin Nd:YVO4 crystal due to the difference between pump power and laser power. For the dual-frequency Nd:YVO4 microcavity laser in this paper, the temperature difference is approximately equal to the temperature difference between the laser gain medium luminescence region and the heat sink, which is about 54 掳C. The relative position of the average wavelength of dual-frequency laser and the peak wavelength of emission spectrum of uncoated thin Nd:YVO4 crystal determined the relative power ratio of dual-frequency laser signal. By controlling the heat sink temperature accurately, the matching degree between the wavelength of dual-frequency laser and the spectrum of gain medium emission cross section is adjusted to realize the output power equalization of dual-frequency laser. When the heat sink temperature is -5.6 掳C, the power equalization is about 0.991.The output power is about 264 mW, and the frequency difference is about 67 GHz. In a series of specific temperature points which can achieve power equalization, the lower heat sink temperature can achieve higher power equalization dual-frequency signal output.
【学位授予单位】：杭州电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN248
【参考文献】
相关期刊论文 前10条
1 朱颖;许颖;方箭;;基于WRC-19 1.13新议题的5G高频段研究概况及展望[J];电信网技术;2016年03期
2 胡淼;张飞;张翔;郑尧元;孙骁;徐亚希;许伟忠;葛剑虹;项震;;用于光生毫米波的双频激光放大特性[J];光学学报;2014年11期
3 方箭;王坦;黄标;;高频段宽带无线通信前瞻[J];电信科学;2014年03期
4 胡淼;黄前锋;张慧;徐国蕊;邓晶;刘晨曦;张飞;;LD抽运的双频固体激光器的光谱和频差特性研究[J];光电子.激光;2014年03期
5 杨清;霍玉晶;段玉生;张艳艳;;用于产生窄带太赫兹波的超大频差双纵模连续激光器[J];光学学报;2013年05期
6 任成;杨星团;张书练;;微片Nd∶YAG双频激光器腔调谐现象研究[J];应用光学;2012年06期
7 赵建涛;冯国英;杨火木;唐淳;陈念江;周寿桓;;薄片激光器热效应及其对输出功率的影响[J];物理学报;2012年08期
8 吴霞;杨苏辉;陈颖;赵长明;刘志杰;;耦合腔结构可调谐双频固体激光器的研究[J];光学学报;2012年03期
9 张书练;;正交偏振双纵模激光器腔调谐物理效应[J];激光与光电子学进展;2011年05期
10 焦明星;邢俊红;刘芸;杨云;马少华;;双腔大频差双频全固态激光器设计与实验研究[J];中国激光;2010年11期
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