窄线宽光纤激光器的微腔稳频及声光调谐技术研究

Narrow-linewidth fiber laser has been widely applied in the coherent optical communication, long-distance fiber sensing, and microwave photonics, and many efforts have been paid to its stability and tunability. On the one hand, with the rapid development of the ultra-high-Q whispering gallery mode (WGM) resonator in recent years, great progress has been made in the research on the frequency stabilization of the narrow-linewidth laser. However, it’s still quite a challenge to enhance the thermal and vibration stability of the WGM resonator, which is crucial to further stabilize the laser. On the other hand, little attention has been paid to the fast tuning speed or wide tuning span, while most research is focused on the narrow linewidth and frequency stabilization. This project will combine the WGM-stabilization and all-fiber acousto-optic (AO) techniques to construct the fast and widely tunable narrow-linewidth frequency-stabilized fiber laser. We will research on the principles of stabilizing and tuning the narrow-linewidth laser, explore the methods to enhance the WGM’s thermal and vibration stability, and fabricate the laser stabilizing and tuning components with WGM resonator and AO effect.

窄线宽光纤激光器在相干光通信、长距离光纤传感和微波光子学等领域具有重要应用，稳频性和调谐性是推进窄线宽激光应用进一步发展的关键。一方面，得益于近年来高品质因子回音廊模微腔的高速发展，窄线宽光纤激光器在稳频性方面取得了长足的进步，然而，目前对于提高回音廊模微腔热稳定性及耦合结构振动稳定性的相关研究还比较滞后，解决这两种稳定性问题对于进一步提高微腔的激光稳频性能非常重要；另一方面，人们在追求更窄线宽、更高稳频度激光的同时，很少将其与高速、大范围的可调谐性结合起来。本项目旨在结合回音廊模稳频技术和全光纤声光调谐技术，研究窄线宽光纤激光器的稳频和调谐原理，探索可以提高微腔热稳定性与振动稳定性的机制，进一步基于该机制研制微腔稳频和声光调谐的核心器件，最终制备出可快速和大范围调谐的窄线宽稳频光纤激光器，为光通信、传感领域提供紧凑的稳频及调谐光源。

本项目旨在结合回音廊模微腔稳频技术和全光纤声光调谐技术，研究窄线宽光纤激光器的稳频和调谐原理，制备微腔稳频和声光调谐的核心器件，研制可快速和大范围调谐的窄线宽稳频光纤激光器，本项目完成的主要内容包括：①基于回音廊模微腔的多模耦合效应构建了窄带上下话路滤波器，并基于该回音廊模微腔滤波器对环形腔光纤激光器进行线宽压缩、稳频和精密调谐；②基于声光效应实现单模光纤基模和高阶模的矢量模耦合，实现了单模光纤中纤芯基模的偏振旋转，并以此为基础构建了在纤式声光可调滤波器，且滤波特性可在带通滤波和带阻滤波之间进行切换；③基于色散补偿光纤的声光矢量模耦合效应实现了一种双波长窄带声光可调谐带通滤波器；④基于耗散孤子-色散傅里叶变换技术对在纤式声光可调滤波器的动态调谐过程进行了测量，并揭示了光纤声光作用的动力学规律；⑤基于在纤式声光可调滤波器实现了一种宽带可调谐的环形腔光纤激光器，该激光器基于光纤纤芯和包层模的矢量模耦合实现声光作用的带通特性，对激光腔内增益进行快速调谐；⑥基于在纤式声光马赫-曾德干涉仪实现了环形腔光纤激光器的双波长可控输出。本项目的研究工作为光纤激光器的稳频和快速大范围调谐提供一种有效的方案，研制出的可快速和大范围调谐的窄线宽稳频光纤激光器，可作为关键光源促进光通信、传感领域的发展。