Patent ID: 8849073

Claim:
An 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 a 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); and wherein: the stress-applying arrangement comprises a pair of rod-like stress-inducing elements (SE 1 , SE 2 ) disposed longitudinally and symmetrically with respect to the core (CO); or the pressure conversion arrangement comprises a pair of rod-like holes (HO 1 , HO 2 ) disposed longitudinally and symmetrically with respect to the core.