光ファイバーを用いた圧力測定におけるプローブ先端形状の検討

抄録

Fiber-optic probes have advantages such as high time resolution on the order of GHz, high spatial resolution on the order of hundreds of microns, corrosion resistance, heat resistance, and pressure resistance. Due to these advantages, application to fluid pressure measurement has been studied. This is useful in the medical field for the development of ultrasonic therapy equipment. However, the signal change of the fiber-optic probe is small concerning the pressure change of the liquid, and it is difficult to measure with high sensitivity. Here, we focused on the tip shape of the fiber-optic probe and investigated the effect on the sensitivity. This study prepared the types of cleave, convex sphere, cone, and truncated cone. We experimented on each shape by immersing it in 6 different concentrations of glycerin-water solutions. We found that the cleave and the convex spherical surface polished with a roughness of 0.02 μm have good sensitivity. Moreover, the cone showed a sensitivity exceeding the theoretical line. From there, the surface roughness and shape of the probe should be selected correctly in pressure measurement.