高稳定性单频光纤激光器研究
发布时间：2019-06-29 15:09
【摘要】：窄线宽单频激光光源在光通信系统、光纤传感、引力波探测和激光雷达等许多领域有着重要应用价值。其中,基于短线性腔结构的单频光纤激光器凭借其紧凑的结构、k Hz量级的线宽和稳定的单纵模运转等优点,已经成为激光领域的研究热点。但是,一般光纤激光器在几百k Hz到几MHz的中频段存在着较强烈的弛豫振荡现象;同时,外界环境扰动和泵浦功率波动容易影响激光器低频段的噪声性能,造成激光输出功率不稳定;并且,自由运转的激光器输出频率波动一般在10-7量级及以上。然而,对于许多实际应用,比如相干光通信和光纤水听器等,目前激光器的稳定性还需要进一步优化。因此,研究如何获得高稳定性的单频光纤激光器具有重要的应用价值和实际意义。本文主要从功率稳定性和频率稳定性两个方面出发,围绕本课题组自制的1.5μm波段单频DBR结构磷酸盐光纤激光器开展以下工作,具体的研究内容和取得的研究成果如下:(1)利用双路光电负反馈系统同时抑制单频光纤激光器的低频段和驰豫振荡处强度噪声,同时提高激光功率长期稳定性。理论上对反馈系统的设计方案、抑制效果和稳定性进行研究;实验上详细地分析泵浦功率可调制的激光器驱动、精密温控和双路反馈系统三个部分电路的设计调试过程。实现了在低频段0-5 k Hz范围内激光器的相对强度噪声(RIN)衰减20 d B左右,在5-10 k Hz范围内降低超过10 d B。特别地,在0.2-5 k Hz处RIN值接近-150 d B/Hz,并且RIN在弛豫振荡峰频率处被抑制约22 d B,同时24小时内激光器输出功率的不稳定性从自由运转时的±0.5%降低至小于±0.05%。通过该反馈系统极大地提高该单频光纤激光器的功率稳定性。(2)通过分析氰化氢(H13C14N)分子吸收谱线,设计基于频率调制光谱技术的稳频实验方案,并开展对单频DBR结构磷酸盐光纤激光器稳频的理论分析和相关实验研究。理论上对稳频系统原理进行数学仿真,并结合定制气室的特性确定实际方案中各项参数。实验上开展稳频研究和对其中各部分电路模块的设计调试过程进行分析和从理论上研究整个闭环系统的稳定性和抑制效果。并且,利用控制腔温度与PZT电压结合的方式对激光器输出频率连续调谐超过3.5 GHz。实现了激光器输出频率波动在±600 k Hz以内,实验上获得了无频率调制的稳频激光。(3)利用前面两项工作的基础,实验上开展对可调制单频光纤激光器的输出激光频率和功率同时稳定的研究。介绍整体实验装置并详细地功率稳定装置的实验过程,通过对二者的同时稳定,使单频激光器的输出激光频率波动在±500 k Hz以内,锁定时间超过24小时,在24小时内激光的长期功率不稳定性小于±0.2%,实验上获得了一台无频率调制的高稳定性单频光纤激光器。
[Abstract]:Narrow linewidth single frequency laser light source has important application value in many fields, such as optical communication system, optical fiber sensing, gravitational wave detection and lidar. Among them, single-frequency fiber laser based on short linear cavity structure has become a research focus in the field of laser because of its compact, k Hz linewidth and stable single longitudinal mode operation. However, there are strong relaxation oscillations in the middle frequency band from hundreds of k Hz to several MHz. At the same time, the noise performance of the laser in the low frequency band is easily affected by the disturbance of the external environment and the fluctuation of the pump power, resulting in the instability of the laser output power. Moreover, the output frequency of the free-running laser generally fluctuates in the order of 10 鈮，
本文编号：2507913
[Abstract]:Narrow linewidth single frequency laser light source has important application value in many fields, such as optical communication system, optical fiber sensing, gravitational wave detection and lidar. Among them, single-frequency fiber laser based on short linear cavity structure has become a research focus in the field of laser because of its compact, k Hz linewidth and stable single longitudinal mode operation. However, there are strong relaxation oscillations in the middle frequency band from hundreds of k Hz to several MHz. At the same time, the noise performance of the laser in the low frequency band is easily affected by the disturbance of the external environment and the fluctuation of the pump power, resulting in the instability of the laser output power. Moreover, the output frequency of the free-running laser generally fluctuates in the order of 10 鈮，
本文编号：2507913
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