Optical curvature sensor based on polarization characteristics of optical fiber

Curvature measurement plays an important role in various applications. An optical curvature sensor based on polarization characteristics of optical fiber is proposed and verified by experiments. The direct bending of the fiber causes a change in birefringence, which results in a change of Stokes parameters of the transmitted light. The large curvature measurement range of tens to more than 100 m(-1) has been realized in the experiment. For micro bending, a cantilever beam structure is used to achieve a sensitivity of up to 12.26/ m(-1 )and a linearity of 99.49% in the measurement range of 0 to 0.15 m(-1), with a resolution of up to 10(-6) m(-1) order of magnitude, which reaches the level of the latest report. The method with the advantages of simple fabrication, low cost and good real-time performance gives a new development direction to the curvature sensor.