Wei Heming, Krishnaswamy Sridhar
Appl Opt. 2020 Jan 10;59(2):530-535. doi: 10.1364/AO.377368.
A fiber-optic Fabry-Perot (FP) interferometer integrated with an adaptive fiber-ring laser is configured as a switchable multi-wavelength fiber laser that can be utilized for ultrasound detection. Because the FP sensor acts as a wavelength filter and a reflector of the fiber-ring laser, the reflective spectrum of the FP sensor changes due to static/dynamic strains, and the wavelength of the laser output shifts accordingly, which is subsequently converted into a corresponding phase shift and demodulated by an unbalanced interferometer. By carefully controlling the polarization of the system, the lasing outputs with a side-mode suppression ratio higher than 30 dB can be obtained, and the lasing linewidth is much narrower than that of the spectrum of the FP sensor. The experiments show that the proposed sensing system has high sensitivity for ultrasound detection and can be adaptive to the low-frequency drifts due to environmental noise.
一种集成了自适应光纤环形激光器的光纤法布里-珀罗（FP）干涉仪被配置为可切换的多波长光纤激光器，可用于超声检测。由于FP传感器充当光纤环形激光器的波长滤波器和反射器，FP传感器的反射光谱会因静态/动态应变而发生变化，激光输出的波长也会相应地发生偏移，随后该偏移被转换为相应的相移并由不平衡干涉仪进行解调。通过仔细控制系统的偏振，可以获得边模抑制比高于30 dB的激光输出，并且激光线宽比FP传感器的光谱线宽窄得多。实验表明，所提出的传感系统对超声检测具有高灵敏度，并且能够适应由于环境噪声引起的低频漂移。
