双频微片激光器功率均衡放大机制

发布时间：2018-05-09 19:31

  本文选题：功率均衡 + MOPA系统　； 参考：《杭州电子科技大学》2017年硕士论文

【摘要】：伴随着爆炸式的信息增长,面对人类日益增长的信息交互需求,通信行业一直致力于寻找新的信息载体,以缓解现如今电磁频谱资源稀缺所带来的压力。向高频进军一直都是业界关注的重点方向。近年来涌现的4G无线通信系统以及其他无线产品大规模应用,使得吉赫兹分米波频段资源变得更为紧张。光载无线通信技术(ROF)以及光生毫米波技术的不断发展,使得对毫米波频段的资源利用成为了一项热门的课题。在光生毫米波技术的众多实验手段中,光外差拍频是一种简单易行的实现方法。双频微片激光器作为一种能够输出高相干度、大频差双频激光的优质激光源,是光外差拍频系统的一个重要组成部分。光外差拍频技术的特点,要求双频激光器能够输出功率均衡,高输出功率的双频激光,本文的内容便围绕这两个议题展开:(1)对毫米波波段以及相关技术背景与前景作了介绍;简要叙述了光生毫米波的几种实现方法,对双频激光光外差拍频法原理的优势进行了说明;之后对微片激光器及MOPA放大系统的近年来研究成果进行了概述。(2)围绕激光原理以及微片激光器的架构分析了4Nd:YVO四能级系统的速率方程、增益系数曲线、增益饱和及双频振荡等内容;基于4Nd:YVO材料的热力学特性,对微片激光器的输出纵模调谐性能做了理论研究。(3)对4Nd:YVO放大器的二级放大机制进行了研究。针对放大器的小信号增益特性、饱和增益特性、放大器结构选择、泵浦光与输入信号光的匹配进行了分析。理论分析结果说明,行波单通二级级联的放大器结构相比双通放大结构,在增益效率、热管理、输出光束质量上具备更大的优势。针对输入信号光和放大器泵浦光之间的光束匹配,以及输入信号光与放大器增益曲线的频谱匹配,进行了理论推导与阐述。(4)搭建MOPA实验装置,引入具备优良冷却性能的TEC温控系统以及透镜组,通过温度调谐与泵浦光束聚焦,获得了良好的频率匹配与光束匹配。当谐振腔温度Tc稳定在16℃时,实现了双频功率均衡的放大激光,总功率为16.1W,双纵模功率比为0.98,频差为53.2GHz,光束质量因数2M=1.20。
[Abstract]:With the explosive growth of information and the increasing demand for information interaction, the communication industry has been working to find new information carriers to alleviate the pressure brought by the scarcity of electromagnetic spectrum resources. To high-frequency march has been the focus of attention in the industry. The emergence of 4G wireless communication systems and other wireless products in large scale in recent years makes the resources of Ghertz decimeter band more scarce. With the development of optical wireless communication (ROF) and millimeter-wave (MMW) technology, the utilization of millimeter-wave (MMW) resources has become a hot topic. Optical heterodyne frequency is a simple and feasible method in many experiments of millimeter-wave technology. Dual-frequency microchip laser is an important part of optical heterodyne beat frequency system as a high quality laser source which can output high coherence and large frequency difference double frequency laser. The characteristics of optical heterodyne beat frequency technology require dual-frequency laser to output power equalization and high output power dual-frequency laser. This paper introduces millimeter-wave band and related technical background and prospect around these two topics. Several realization methods of millimeter wave generated by light are briefly described, and the advantages of the principle of double frequency laser heterodyne beat method are explained. Secondly, the research results of microchip laser and MOPA amplification system in recent years are summarized. (2) the rate equation and gain coefficient curve of 4Nd:YVO four-level system are analyzed around the principle of laser and the structure of microchip laser. Gain saturation and dual-frequency oscillation. Based on the thermodynamic properties of 4Nd:YVO, the output longitudinal mode tuning performance of microchip laser is theoretically studied. (3) the second-order amplification mechanism of 4Nd:YVO amplifier is studied. The small signal gain characteristic, saturation gain characteristic, amplifier structure selection and the matching between pump light and input signal light are analyzed. The theoretical analysis results show that the two-stage cascaded traveling-wave amplifier structure has more advantages in gain efficiency, thermal management and output beam quality than the double-pass amplifier structure. Aiming at the beam matching between the input signal light and the amplifier pump light, and the spectrum matching between the input signal light and the amplifier gain curve, the theoretical derivation and elaboration of the MOPA experimental device are carried out. The TEC temperature control system and lens group with excellent cooling performance are introduced, and good frequency matching and beam matching are obtained by tuning temperature and focusing the pump beam. When the cavity temperature Tc is stable at 16 鈩，

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