摘要 |
A plurality of optical fibers is embedded in a helical shape in a cylindrical attachment layer of the external periphery of a form body having a circular cross section. The optical fibers are deformed by the deformation generated in the form body due to bending, twisting, or elongating deformation produced by external pressure of the form body. A three-dimensional position after deformation produced by the bending, twisting, or elongating deformation of the form body is measured using the phase change or change in frequency in Rayleigh scattering or Brillouin scattering, which is scattered light from a pulse laser light emitted into the optical fiber, the phase change or change in frequency being generated by the deformation. |