Force and acceleration sensor using four wave mixing technique
View Patent ↗A sensor for measuring force, the sensor including: a light source; and a mixing medium in optical communication with the light source and exposed to the force; wherein four wave mixing of light interacting with the mixing medium provides a signal that indicates the force.
1. A sensor for measuring force, the sensor comprising:
a light source; and
a mixing medium in optical communication with the light source and exposed to the force;
wherein four wave mixing of light interacting with the mixing medium provides a signal that indicates the force.
2. The sensor as in claim 1 , further comprising at least one additional light source configured to illuminate the mixing medium.
3. The sensor as in claim 1 , wherein the light source comprises at least one of a laser and a broadband light source coupled to an optical filter.
4. The sensor as in claim 1 , wherein the light source is configured to vary a wavelength of light emitted from the light source.
5. The sensor as in claim 1 , further comprising a beam combiner optically coupled to the mixing medium and to the light source.
6. The sensor as in claim 1 , further comprising a light detector optically coupled to the mixing medium and configured to detect light emitted from the mixing medium.
7. The sensor as in claim 6 , wherein the light detector comprises at least one of an optical spectrum analyzer, a photomultiplier tube and a photodiode.
8. The sensor as in claim 1 , wherein the mixing medium comprises a birefringent material.
9. The sensor as in claim 8 , wherein the birefringent material comprises at least one of an optical fiber and a crystal.
10. The sensor as in claim 1 , wherein the mixing medium comprises periodically poled lithium niobate.
11. The sensor as in claim 1 , wherein the mixing medium comprises a gallium-arsenide (GaAs)/aluminum-gallium-arsenide (AlGaAs) semiconductor structure.
12. The sensor as in claim 1 , further comprising a grating optically coupled to the mixing medium, the grating configured to spatially separate light emitted from the mixing medium.
13. The sensor as in claim 1 , further comprising a proof mass coupled to the mixing medium wherein the proof mass is configured to physically change the mixing medium in response to a change in gravitational force.
14. A method for measuring force, the method comprising:
exposing a mixing medium to the force;
illuminating the mixing medium with at least two beams of light, wherein the light interacts with the mixing medium by four wave mixing of the light;
measuring a characteristic of light emitted from the mixing medium as a result of the four wave mixing; and
determining the force from the measured characteristic.
15. The method as in claim 14 , wherein the characteristic comprises at least one of intensity and wavelength of a Stokes wave.
16. The method as in claim 14 , wherein the characteristic comprises at least one of intensity and wavelength of an anti-Stokes wave.
17. The method as in claim 14 , further comprising:
exposing the mixing medium to at least one of temperature and pressure; and
determining the at least one of temperature and pressure from the measured characteristic.
18. The method as in claim 14 , wherein the force is gravitational force.
19. The method as in claim 14 , wherein the method is implemented by instructions stored on machine-readable media.
20. A system for measuring force in a borehole, the system comprising:
a logging instrument configured to be conveyed through the borehole, the logging instrument comprising:
a light source;
a mixing medium in optical communication with the light source and exposed to the force, wherein four wave mixing of light interacting with the mixing medium provides light with a characteristic that indicates the force; and
a light detector in optical communication with the mixing medium and configured to measure the characteristic.