Pressure and Measurement by Means of An Optical Fiber

A method of measuring pressure comprising:

• a preparation step in which an optical fiber (FD) is placed in an environment (ENV) in which pressure needs to be measured;
• said optical fiber (FD) comprising a core (CO);
• a cladding (CL) surrounding and contacting the core, a pressure conversion arrangement (HO) embedded in the cladding for converting isotropic external pressure applied to the optical fiber into pressure-dependent anisotropic stress applied to the core, the pressure conversion arrangement being disposed with respect to the stress-applying arrangement so that the pressure-dependent anisotropic stress enhances the deformation of the core caused by the constant anisotropic stress;
• a hollow stress-applying arrangement (SE) embedded in the cladding for applying constant anisotropic stress on the core, wherein the pressure conversion arrangement (HO) is comprised within the hollow stress-applying arrangement (SE).
• a light injecting step in which light (LI) is injected into the optical fiber (FD), so as to obtain a response (LR);
• and
• a measurement step in which a physical parameter (Δλ) of the response that varies as a function of birefringence of the core (CO) is measured.