Curvature measurement plays an important role in many fields. Aiming to overcome\nshortcomings of the existing optical fiber curvature sensors, such as complicated structure and\ndifficulty in eliminating temperature noise, we proposed and demonstrated a simple optical fiber\ncurvature sensor based on surface plasmon resonance. By etching cladding of the step-index\nmultimode fiber and plating gold film on the bare core, the typical Kretschmann configuration is\nimplemented on fiber, which is used as the bending-sensitive region. With increases in the curvature\nof the optical fiber, the resonance wavelength of the SPR (Surface Plasmon Resonance) dip linear\nred-shifts while the transmittance decreases linearly. In the curvature range between ..... the wavelength sensitivity reached .... and the intensity sensitivity reached ... In addition, with increases in the ambient temperature, the resonance wavelength of the SPR dips\nlinearly blueshifts while the transmittance increases linearly. In the temperature range between 20\nand ..., the wavelength sensitivity is ... and the intensity sensitivity is ... The sensing matrix is built up by combining the aforementioned four sensitivities. By means of\nthe dual modulation method, the cross-interference caused by temperature change is eliminated.\nAdditionally, simultaneous measurement of curvature and temperature is realized.
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