Back to results
US 4,900,918 AGranted
Resonant fiber optic accelerometer with noise reduction using a closed loop feedback to vary pathlength
AssigneeAllied-Signal Inc.
InventorKevin M. Killian
Life of this patent
Estimating the term…
Abstract
A pair of resonant optical cavities are used to measure shifts in length of a beam which deflects under acceleration. One end of each optical cavity is highly reflective and the other end partially reflective, thus permitting resonating light to exit the resonators. The light outputs of the two resonators is combined and the resultent beat frequency is used to detect deflections of the beam.
Claims12
Accelerometer is which a proof mass is suspended by a cantilever beam, and deflection of the beam is proportional to acceleration, characterized by:
- two resonant light paths, the light paths being rendered unequal in length by the deflection of the beam;
- a common light source connected to the light paths;
- a means to obtain optical outputs representative of light resonating in each of the light paths;
- means to merge the optical outputs;
- photodetection means responsive to the merged optical outputs and sensitive to changes in the character of light as a result of said unequal path lengths;
- and
- a feedback loop including first means in one of the light paths and second means connected to the first means and to the photodetection means, said first means varying the length of the one light path to equalize the lengths of the two light paths which have been rendered unequal by the acceleration, said second means applying a signal to the first means commensurate with said acceleration.
4 more elements
Dependencies are inferred from the claim text.