波长扫描激光器线宽的动态测量

发布时间：2018-03-29 01:14

本文选题：延时外差　切入点：光谱线宽　出处：《北京交通大学》2015年硕士论文

【摘要】：摘要：基于SOA的可调谐光纤环形腔激光器在光纤传感、光纤通信、光信息处理、非线性光学、特别是医疗器械仪器设备等领域有着重要的应用,是光纤传感和光学相干层析技术中的关键部件,其工作性能直接影响整个光学相干层析技术系统,其动态输出光谱特性决定了传感与成像系统的分辨率水平,因此对其动态输出光谱特性尤其是光谱线宽的测量有着重要的意义。本文理论分析了基于SOA的光纤环形腔激光器的工作机制和输出光谱特性,讨论了测量动态输出光谱线宽的可行性,并采用了一种基于马赫-增德干涉结构改进的延时外差方法对实验室自制的环形腔激光器固定波长和波长扫描两种工作状态下的光谱线宽特性进行测量,得到了波长扫描状态下波长扫描频率与光源相干特性的关系。采用了一种新型的利用电光调制器(EOM)调制截取输出激光的方法对环形腔激光器波长扫描工作方式的输出光谱进行直接动态测量,实现了对傅里叶域锁模状态下连续宽谱光源任意波长线宽特性的直接测量,并通过实验研究了调制光脉冲的时域特性对输出光谱特性的影响。一系列研究结果表明,两种不同工作机制运行的测量方案对输出光谱线宽结果不同但是存在关系,利用EOM直接测量的方法比延时外差法测得的光谱线宽略大,波长扫描频率为60kHz时,延时外差法测量激光器输出光谱线宽在5pm,利用EOM方法测得为37pm。实验结果证明了两种方法在波长扫描状态下激光器输出光谱线宽测量领域各自的优越性和局限性,为深入理解光纤环形腔激光器工作机制提供了依据,并为实现直接实时测量连续宽谱光源的光谱特性打下了基础。
[Abstract]:Abstract: tunable fiber ring cavity lasers based on SOA have important applications in the fields of optical fiber sensing, optical fiber communication, optical information processing, nonlinear optics, especially medical instruments and equipment. It is a key component in optical fiber sensing and optical coherence tomography technology. Its performance directly affects the whole optical coherence tomography system. Its dynamic output spectral characteristics determine the resolution level of the sensing and imaging system. Therefore, it is of great significance to measure the dynamic output spectral characteristics, especially the spectral linewidth. In this paper, the working mechanism and output spectral characteristics of fiber ring cavity laser based on SOA are theoretically analyzed, and the feasibility of measuring dynamic output spectral linewidth is discussed. A modified time-delay heterodyne method based on Mach Zende interference structure is used to measure the spectral linewidth characteristics of a self-made ring cavity laser in two working states: fixed wavelength and wavelength scanning. The relationship between the wavelength scanning frequency and the coherent characteristics of the light source under wavelength scanning is obtained. A new method using electro-optic modulator EOM modulation to intercept the output laser is proposed for the wavelength scanning mode of the ring cavity laser. Direct dynamic measurement of the output spectrum, The direct measurement of arbitrary wavelength linewidth characteristics of continuous wide-spectrum light source in mode-locked state in Fourier domain is realized. The influence of the time-domain characteristics of modulated light pulses on the output spectral characteristics is studied experimentally. A series of results show that, Two kinds of measurement schemes with different working mechanisms have different results on the output spectral linewidth, but there is a relationship between them. The direct measurement method using EOM is a little larger than that measured by delay heterodyne method, and the wavelength scanning frequency is 60kHz. The output spectral linewidth of the laser is measured by delay heterodyne method at 5 pm and by EOM method at 37 pm. The experimental results demonstrate the advantages and limitations of the two methods in the field of laser output spectral linewidth measurement under wavelength scanning. It provides a basis for further understanding the working mechanism of fiber ring laser, and lays a foundation for the realization of direct real-time measurement of spectral characteristics of continuous wide spectrum light source.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN248

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