The performance of sensors, including optical fiber sensors, is commonly limited by the tradeoff between a large dynamic range and a high resolution. In this Letter, in order to optimize both, we propose an inline multimode interferometer sensor based on a suspended-core microstructured optical fiber. Due to the existence of multiple pairs of mode interferences, the transmission spectrum of the interferometer consists of dense fringes modulated by a lower envelope. Since these mode interferences take place in the uniform material with the same length, the dense fringes and the lower envelope have an identical sensing response without crosstalk. Hence, the sensor integrates the large dynamic range of the lower envelope and the high resolution of the dense fringes. Strain-sensing performance is investigated to validate the characteristic of the large dynamic range and the high resolution of the proposed sensor. The dynamic range, theoretically 0-9200 µɛ, is 12 times larger than for the dense fringes, and the resolution is 17.5 times higher than for the lower envelope.

中文翻译：

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基于悬浮纤芯微结构光纤的高分辨率，大动态范围多模干涉仪传感器。

传感器（包括光纤传感器）的性能通常受大动态范围和高分辨率之间的权衡限制。在这封信中，为了同时优化两者，我们提出了一种基于悬浮纤芯微结构光纤的在线多模干涉仪传感器。由于存在多对模式干扰，干涉仪的传输频谱由由较低包络调制的密集条纹组成。由于这些模式干扰发生在长度相同的均匀材料中，因此密集的条纹和下包络线具有相同的感测响应，而不会产生串扰。因此，该传感器整合了下包络线的大动态范围和密集条纹的高分辨率。研究了应变传感性能，以验证所提出传感器的大动态范围和高分辨率特性。理论上的动态范围为0-9200 µl，比密集条纹大12倍，分辨率比低包络线大17.5倍。