Fiber optic pressure sensor

A pressure sensor comprising:

• a structure having a first blind aperture on a first end and a second blind aperture on an opposite end, the first blind aperture and/or the second blind aperture offset from the central axis, the first blind aperture and the second blind aperture having sufficient depth for a common sidewall of the first blind aperture and the second blind aperture to form a diaphragm;
• the first blind aperture configured to be coupled to a source of pressure;
• the second blind aperture common sidewall forming the diaphragm having a region of maximum deflection upon application of a pressure to the first blind aperture and a region of minimum deflection upon application of a pressure to the first blind aperture, the region of maximum deflection and the region of minimum deflection in thermal equilibrium with each other;
• a first optical fiber having a first fiber Bragg grating (FBG) attached to the region of maximum deflection, and a second optical fiber having a second FBG attached to the region of minimum deflection;
• a controller measuring a reflected or transmitted wavelength in the first FBG and second FBG to determine at least one of a pressure or a temperature;
• where the controller estimates a pressure Pm1 or Pm2 from a transmitted or reflected wavelength from the first FBG and second FBG, the first FBG wavelength and the second FBG wavelength converted into a pressure by the controller configured to compute:
• Pm1=C1λ1m1−C1λ01+C2λ2m1−C2λ02
• Pm2=C1λ1m2−C1λ01+C2λ2m2−C2λ02
• where:
• C1, C2, λ01, and λ02 are calibration constants.

A pressure sensor comprising:

• a structure having a first blind aperture on a first end and a second blind aperture on an opposite end, the first blind aperture and second blind aperture separated by a diaphragm, the diaphragm formed by a common sidewall of the first blind aperture and the second blind aperture, the aperture deflecting in a direction perpendicular to a central axis of the first blind aperture or the second blind aperture in response to an applied pressure;
• the first blind aperture configured to be coupled to a source of pressure causing a deflection of the diaphragm;
• the diaphragm having a region of maximum deflection upon application of a pressure to the first blind aperture and a region of minimum deflection upon application of a pressure to the first blind aperture;
• a first fiber Bragg grating (FBG) attached to the region of diaphragm maximum deflection, and a second FBG attached to the region of diaphragm minimum deflection;
• a controller configured to measure a wavelength of the first FBG and a wavelength of the second FBG and determine a pressure applied to the first blind aperture;
• where the controller converts the first FBG wavelength or the second FBG wavelength to a temperature Tn1 or Tn2 by computing:
• Tn1=C3λ1n1−C3λ01+C4λ2n1−C4λ02
• Tn2=C3λ1n2−C3λ01+C4λ2n2−C4λ02
• where C3, C4, λ01, and λ02 are calibration constants.