Systems and methods for distributed pressure sensing

摘要

A pressure sensing cable in one embodiment includes a polarization maintaining (PM) optic fiber having a length; and a Fiber Bragg Grating (FBG) pair formed in the PM optic fiber. The FBG pair includes a first FBG formed at a location along the length of the optic fiber. The first FBG defines a first wavelength range at which the first FBG is reflective. The FBG pair also includes a second FBG spaced a distance from the first FBG to define a FBG cavity extending between the first FBG and the second FBG. The second FBG defines a second wavelength range at which the second FBG is reflective. The first wavelength range of the first FBG and the second wavelength range of the second FBG at least partially overlap.

主权项

1. A measurement system comprising:
a pressure sensing cable comprising:
a polarization maintaining (PM) optic fiber having a length; andplural Fiber Bragg Grating (FBG) pairs formed along the length of the optic fiber, each FBG pair comprising:
a first FBG pair member formed at a location along the length of the optic fiber, the first FBG pair member defining a first wavelength range at which the first FBG pair member is reflective; anda second FBG pair member spaced a distance from the first FBG pair member to define a FBG cavity extending between the first FBG pair member and the second FBG pair member, the second FBG pair member defining a second wavelength range at which the second FBG pair member is reflective; wherein the first wavelength range of the first FBG pair member and the second wavelength range of the second FBG pair member of each pair at least partially overlap with each other but not with wavelength ranges of members of other FBG pairs; one or more processors operably coupled to the pressure sensing cable and configured to transmit an optic signal to the pressure sensing cable; and the one or more processors further configured to:
receive a return signal including reflections of the optic signal transmitted to the pressure sensing cable, the reflections including a corresponding reflection from each of the FBG cavities of the FBG pairs;identify a portion of the return signal corresponding to each FBG pair based on the wavelength ranges of the members of each FBG pair;determine, using the portion of the return signal corresponding to each FBG pair, a pressure corresponding to the portion of the return signal identified for each FBG pair.