关键词: 光纤传感器, 模式干涉仪, 双锥级联, 锥形光纤, 角度传感器

Abstract:

This paper proposes a simple-fabricated and high sensitive angle sensor based on single mode optical fiber. The sensor consists of two cascading abrupt-tapers with different sizes, fabricated with CO₂ laser. The cladding modes are excited in the first taper and interfered with the core mode in the second taper. When an angle applied on the sensor, length between the two tapers changes. At the same time, the first taper is bent, affecting the ratios and effective indices of the core mode, and the cladding modes excited by the first taper. As a consequence, the interference pattern has a shift. By monitoring the shift, angle measurement is achieved. Experimental results show that the sensor has a good linear relation in a certain measurement range. Sensitivity of the angle measurement is as high as 601.8 nm/(°) between 0.057 5° and 0.075 0°.

Key words: fiber sensor, modal interferometer, tapered fiber, two cascading abrupt-taper, angle sensor