Patent ID: 6912912

Claim:
A pressure sensor, comprising: an optical waveguide having: a cladding-free optical fiber with a given refractive index; a flexible, tube-shaped, extruded sheath having locally limited support points; said optical fiber being disposed in said sheath and supporting said sheath thereon only at said locally limited support points to define an intermediate space therebetween surrounding said optical fiber; said optical fiber being disposed in said sheath surrounded by said intermediate space in an unloaded state of said sheath when no pressure is applied to said optical waveguide; a medium filling said intermediate space and surrounding said optical fiber, said medium having a refractive index less than said given refractive index; and said sheath being elastic and resting at least at a local point on said optical fiber when pressure is applied to said optical waveguide such that propagation of light in said optical waveguide is attenuated even without deformation of said optical fiber.