Abstract The vortex beam owns helical phase factor, orbital angular momentum, and hollow structure of intensity distribution. It is widely applied in information coding, optical manipulation and optical sensing. This paper attempts to design a fiber Bragg temperature sensor based on vortex light, including an orbital angular momentum (OAM) beam transmitted by fiber Bragg grating (FBG), an optical fiber path used to eliminate errors, and a Gaussian beam, which is used to interfere with FBG transmission light. The interference pattern of a Gaussian beam and an OAM beam rotates with the changes of phase difference between the two beams. When the temperature changes, FBG is affected by the thermal optical effect and thermal expansion effect, and the central wavelength of the reflected spectrum will shift. Based on the relationship between wavelength shift and temperature change, temperature measurement in a large range can be realized. Additionally, the Filter is placed behind the FBG, and the transmission light ( λ = 1.466 μ m ) with less reflection is selected to interfere with the Gaussian light, with the change of phase of transmission light, the rotation of the interference pattern will change accordingly. The temperature change corresponding to the 2π rotation of the interference pattern can be obtained, thus temperature measurement with high resolution can be realized. The simulation results show that when the temperature range is 27 °C–427 °C, the sensitivity of this sensor is 14.42 pm/°C. On the basis of the rotation of the interference pattern, when the rotation angle of the temperature-induced interference pattern change within 2π the temperature sensitivity is 1.529 rad/°C, based on the angular resolution of CCD, the theoretical resolution of temperature measurement is 6.3e−7 °C. Similar to the cursor effect, the main ruler measures a wide range of temperature changes according to wavelength drift, and the cursor is a high-resolution measurement of temperature according to the rotation angle of the interference pattern.

中文翻译：

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具有涡旋光束的高分辨率和大范围光纤布拉格光栅温度传感器

摘要 涡旋光束具有螺旋相位因子、轨道角动量和强度分布中空结构。它广泛应用于信息编码、光学操纵和光学传感。本文尝试设计一种基于涡旋光的光纤布拉格温度传感器，包括由光纤布拉格光栅（FBG）传输的轨道角动量（OAM）光束、用于消除误差的光纤路径和高斯光束，其使用干扰FBG传输光。高斯光束和OAM光束的干涉图随着两光束相位差的变化而旋转。当温度变化时，FBG受到热光效应和热膨胀效应的影响，反射光谱的中心波长会发生偏移。基于波长漂移与温度变化的关系，可以实现大范围的温度测量。另外，在FBG后面放置Filter，选择反射较少的透射光（λ=1.466μm）干涉高斯光，随着透射光相位的变化，干涉图的旋转也会发生变化因此。可以得到干涉图2π旋转对应的温度变化，从而实现高分辨率的温度测量。仿真结果表明，当温度范围为 27°C–427°C 时，该传感器的灵敏度为 14.42 pm/°C。在干涉图样旋转的基础上，当温度诱导干涉图的旋转角度在2π内变化时，温度灵敏度为1.529 rad/°C，基于CCD的角分辨率，温度测量的理论分辨率为6.3e-7°C。类似于光标效应，主尺根据波长漂移测量大范围的温度变化，光标是根据干涉图的旋转角度高分辨率测量温度。