Interferometric fiber optic displacement sensor
Abstract
A method is presented to produce a change in the optical path length in the gap between two single mode optical fibers proportional to the lateral displacement of either fiber end normal to its axis. This is done with the use of refraction or diffraction at the interface between a guiding and non-guiding media to change the direction of propagation of the light in the gap. A method is also presented for laying a waveguide on a cantilever so that the displacement of the tip of the cantilever produces a proportional path length change in the gap by distancing the waveguide from the neutral axis of the cantilever. The fiber is supported as a cantilever or a waveguide is deposited on a micromachined cantilever and incorporated in an interferometer which is made totally on a silicon substrate with the use of integrated-optic technology. A resonant element in the form of a micro-bridge is incorporated in the ridge waveguide and produces a frequency output which is readily digitizeable and immune to laser frequency noise. Finally, monolithic mechanical means for phase modulation are provided on the same sensor substrate. This is done by vibrating the cantilever or micro-bridge either electrically or optically.
- Inventors:
- Issue Date:
- Research Org.:
- Optisensors, Inc., Cambridge, MA (United States)
- Sponsoring Org.:
- USDOE
- OSTI Identifier:
- 872240
- Patent Number(s):
- 5891747
- Application Number:
- 08/456,189
- Assignee:
- Farah, John, Cambridge, MA (United States)
- Patent Classifications (CPCs):
-
G - PHYSICS G01 - MEASURING G01B - MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS
G - PHYSICS G01 - MEASURING G01D - MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE
- DOE Contract Number:
- FG02-90ER81033
- Resource Type:
- Patent
- Resource Relation:
- Patent File Date: 1995 May 30
- Country of Publication:
- United States
- Language:
- English
- Subject:
- /438/356/
Citation Formats
Farah, John. Interferometric fiber optic displacement sensor. United States: N. p., 1999.
Web.
Farah, John. Interferometric fiber optic displacement sensor. United States.
Farah, John. Fri .
"Interferometric fiber optic displacement sensor". United States. https://www.osti.gov/servlets/purl/872240.
@article{osti_872240,
title = {Interferometric fiber optic displacement sensor},
author = {Farah, John},
abstractNote = {A method is presented to produce a change in the optical path length in the gap between two single mode optical fibers proportional to the lateral displacement of either fiber end normal to its axis. This is done with the use of refraction or diffraction at the interface between a guiding and non-guiding media to change the direction of propagation of the light in the gap. A method is also presented for laying a waveguide on a cantilever so that the displacement of the tip of the cantilever produces a proportional path length change in the gap by distancing the waveguide from the neutral axis of the cantilever. The fiber is supported as a cantilever or a waveguide is deposited on a micromachined cantilever and incorporated in an interferometer which is made totally on a silicon substrate with the use of integrated-optic technology. A resonant element in the form of a micro-bridge is incorporated in the ridge waveguide and produces a frequency output which is readily digitizeable and immune to laser frequency noise. Finally, monolithic mechanical means for phase modulation are provided on the same sensor substrate. This is done by vibrating the cantilever or micro-bridge either electrically or optically.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Jan 01 00:00:00 EST 1999},
month = {Fri Jan 01 00:00:00 EST 1999}
}
Works referenced in this record:
Micromachined silicon cantilever beam accelerometer incorporating an integrated optical waveguide
conference, March 1993
- Burcham, Kevin E.; De Brabander, Gregory N.; Boyd, Joseph T.
- Fibers '92, SPIE Proceedings
A scanning force microscope with a fiber‐optic‐interferometer displacement sensor
journal, May 1991
- Mulhern, P. J.; Hubbard, T.; Arnold, C. S.
- Review of Scientific Instruments, Vol. 62, Issue 5