Patent ID: 7315666

Claim:
A method for measuring pressure and other physical data by means of a coiled optical fiber which is embedded in the wall of a carrier tube, wherein a pulsed laser light source transmits a sequence of light pulses of a selected wavelength from one end of the fiber into an elongate substantially uniform light guide channel provided by said optical fiber; and wherein a light sensor assembly, which is located near said end of the fiber, detects any shift in wavelength of the light pulses backscattered from various locations along the length of said light guide channel and a signal processing assembly calculates on the basis of the detected wavelength pattern of the backscattered light a strain pattern along at least a substantial part of the length of the fiber, and determines on the basis of the calculated strain pattern a pressure difference between the interior and exterior of the carrier tube and other physical data at various locations along the length of the carrier tube; wherein a plurality of optical fibers are embedded in the wall of the carrier tube and are arranged in different substantially helical configurations relative to a longitudinal axis of the tube, which fibers are each connected to a common signal processing assembly which compares optical signals reflected along the length of said optical fibers to determine the effects of deformation of the carrier tube resulting from bending and/or torque forces exerted on various locations along the length of the carrier tube and/or temperature variations at various locations along the length of the carrier; and wherein said helical configurations are selected from the group consisting of helical fibers having opposite pitch angles, helical fibers which are wound substantially co-axially and at different diameters relative to a longitudinal axis of the carrier tube, helical fibers of which the helixes have substantially different pitch angles, and combinations thereof.