Dual cavity displacement sensor
AssigneeSymphony Acoustics, Inc.
InventorDustin Wade Carr
Life of this patent
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Abstract
An optical displacement sensor is disclosed comprising a beam splitter having two optically coupled and mechanically coupled optically resonant cavities. The respective cavity lengths of the optically resonant cavities are functions of an environmental stimulus. By virtue of the optically coupled optically resonant cavities, the output of the beam splitter is less sensitive to input wavelength variation yet retains high sensitivity to the environmental stimulus.
Claims17
An apparatus comprising an optical element for receiving an input of optical energy and distributing the optical energy into a first output and a second output, wherein the optical element comprises;
- (a) a first surface;
- (b) a second surface;
- and
- (c) a movable membrane, wherein the movable membrane interposes the first surface and the second surface;
- wherein the first surface and the membrane are substantially parallel and form a first optically resonant cavity having a first cavity length, and wherein the first cavity length varies in response to an environmental stimulus;
- wherein the second surface and the membrane are substantially parallel and form a second optically resonant cavity having a second cavity length, and wherein the second cavity length varies in response to the environmental stimulus;
- and
- wherein the ratio of optical energy in the first output to the optical energy in the second output is a function of the first cavity length and the second cavity length.
An optical displacement sensor comprising:
- (1) a source of input light, wherein the input light is characterized by a first wavelength;
- (2) an optical element for receiving the input light and distributing it into a first optical output and a second optical output, wherein the ratio of the first optical output to the second optical output is a function of an environmental stimulus, and wherein the optical element comprises;
- (a) a first optical cavity that is optically resonant at the first wavelength, wherein said first optical cavity has a first cavity length that is a function of the environmental stimulus;
- and
- (b) a second optical cavity that is optically resonant at the first wavelength, wherein said second optical cavity has a second cavity length that is a function of the environmental stimulus;
- wherein the first optical cavity and the second optical cavity are mechanically coupled such that the sum of the first cavity length and the second cavity length is substantially constant;
- and
- (3) a first photodetector for providing a first electrical output based on one of the first optical output and the second optical output.
Dependencies are inferred from the claim text.