基于二次电光效应的单频激光快速线性调频技术研究

Narrow-linewidth, high-stability CW laser source with high-speed continuous linear frequency sweep capabilities can be used in many fields, including synthetic aperture laser radar, coherent laser communication, high resolution spectroscopy, optical processing of radiofrequency signals, coherent manipulation of atoms, therefore the study of the coherent fast linear frequency sweep technologies has scientific significance. In this project, a novel electro-optic phase modulator based on quadratic electro-optic effects is introduced into serrodyne optical frequency translation,so that wide-range fast linear sweep of single-frequency laser can be achieved by using a sawtooth drive with fixed frequency out of the cavity. The main researched contents include: a theoretical model building of serrodyne optical frequency translation by Fourier expansion of the light field phase; simulation of the key system features to get the key system parameters, including the effects of sawtooth waveform parameters on the laser frequency, linewidth and high order sidebands; preparing and testing the related phase modulator, and building an experimental demonstration of the frequency sweep system. This project is expected to develop a rapid continuous linear sweep laser technology, providing some theoretical foundations and supports for laser frequency sweep technologies development.

窄线宽、高稳定、宽带线性调谐的连续激光光源在合成孔径激光雷达、激光相干通信、高分辨率光谱、射频信号光学产生、原子相干操纵等领域有着重要应用，故单频激光器的快速线性调频技术研究具有重要意义。本项目将二次电光效应的电光相位调制器应用到线性光频转换技术中，利用固定频率的锯齿波驱动在激光器外部实现单频激光器的大范围快速线性调频。研究内容有：对激光相位利用傅里叶级数进行展开，建立线性光频转换技术的理论模型；在理论模型的基础上，对系统的一些关键特性进行仿真计算，包括锯齿波各参数对激光频率、线宽及各阶衍生频率的影响，得到系统的关键参数；根据得到的关键参数，对基于二次电光效应的电光相位调制器进行制备与测试，并利用该器件搭建一套实验演示系统，对所得到的调频性能进行测试。项目有望实现具有高转换效率的连续快速线性调频，为激光器线性调频技术的发展提供新的学术基础和技术手段。

窄线宽、高稳定、宽带线性调谐的激光光源在合成孔径激光雷达、激光相干通信、高分辨率光谱、射频信号光学产生、原子相干操纵等领域有着重要应用，本项目根据计划书的要求开展了单频激光快速线性调频技术的研究工作。对激光器的相频噪声抑制技术进行了系统研究，利用基于光纤光栅FP腔的自注入锁定半导体激光器将半导体激光器的本征线宽从数MHz压缩到125 Hz，并在此基础上对窄线宽激光利用电光调制器进行调制，将产生的高阶调制边带注入到半导体激光器中进行锁定，实现了窄线宽激光的线性调频，调频范围为15 GHz，调频速度为2.5 THz/s。项目总共发表SCI收录的学术论文9篇，EI收录的学术论文4篇，申请发明专利6项，其中4项已经授权，项目同时协助培养了2名博士研究生及1名硕士研究生。