Caldas Paulo, Jorge Pedro A S, Rego Gaspar, Frazão Orlando, Santos José Luís, Ferreira Luís Alberto, Araújo Francisco
Instituto de Engenharia de Sistemas e Computadores do Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal.
Appl Opt. 2011 Jun 10;50(17):2738-43. doi: 10.1364/AO.50.002738.
In this work an all-optical hot-wire flowmeter based on a silver coated fiber combining a long period grating and a fiber Bragg grating (FBG) structure is proposed. Light from a pump laser at 1480 nm propagating down the fiber is coupled by the long period grating into the fiber cladding and is absorbed by the silver coating deposited on the fiber surface over the Bragg grating structure. This absorption acts like a hot wire raising the fiber temperature locally, which is effectively detected by the FBG resonance shift. The temperature increase depends on the flow speed of the surrounding air, which has the effect of cooling the fiber. It is demonstrated that the Bragg wavelength shift can be related to the flow speed. A flow speed resolution of 0.08 m/s is achieved using this new configuration.
在这项工作中，提出了一种基于镀银光纤的全光热线流量计，该光纤结合了长周期光栅和光纤布拉格光栅（FBG）结构。来自1480 nm泵浦激光器的光沿光纤向下传播，通过长周期光栅耦合到光纤包层中，并被沉积在布拉格光栅结构上方光纤表面的银涂层吸收。这种吸收作用类似于热线，使光纤局部温度升高，而这可以通过FBG共振位移有效地检测到。温度升高取决于周围空气的流速，空气具有冷却光纤的作用。结果表明，布拉格波长位移与流速有关。使用这种新配置实现了0.08 m/s的流速分辨率。
