Optical Sensing Device Containing Fiber Bragg Gratings

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Abstract:

A new optical sensing device containing fiber Bragg gratings a scanning bandpass filter, an interferometer and multiple photodetectors is disclosed. The present invention also describes a new system and method for fibre Bragg grating FBG sensor interrogation and multiplexing. The new system combines a scanning Fabry-Perot SEP bandpass filter used to wavelength-multiplex multiple gratings in a single fiber, and an unbalanced Mach-Zehnder fibre interferometer made with a 3 x 3 coupler to detect strain-induced wavelength shifts. A passive technique for interferometer drift compensation using non-sensing FBGs is included in the system. A complete prototype system interrogates four gratings in a single fiber at a Nyquist sampling rate up to 10 kHz, with a noise floor measured near 4 nEpsilon Hz-2 above 0.1 Hz. The inclusion of the interferometer drift compensation technique is shown to make quasi-static measurements feasible.

Author(s):
Todd, Michael D.
Author Organization(s):
DEPARTMENT OF THE NAVY WASHINGTON DC
Descriptive Note:
Patent application, filed 1 Aug 2000
Pagination:
0033

Security Markings

DOCUMENT & CONTEXTUAL SUMMARY

Distribution:
Approved For Public Release

RECORD

Collection: TR
Identifying Numbers
Report Number(s):
PAT-APPL-09 917 643
Monitor Series:
NRL
 Subject Terms
Joint Capability Areas:
JCA_6_Net Centric; JCA_6.1_Information Transport; JCA_1.3_Human Capital Management; JCA_1_Force Support; JCA_1.3.2_Personnel Management; JCA_3.2_Engagement; JCA_3_Force Application
Modernization Areas:
Microelectronics
Communities of Interest:
Sensors
Descriptor(s):
*FIBER OPTICS, *PATENT APPLICATIONS, *OPTICAL DETECTORS, PASSIVE SYSTEMS, GRATINGS(SPECTRA), FABRY PEROT INTERFEROMETERS, PHOTODETECTORS, MULTIPLEXING, BANDPASS FILTERS, BRAGG ANGLE
Field(s)/Group(s):
Optical Detection and Detectors, Fiber Optics and Integrated Optics
Keyword(s):
*FIBER OPTIC SENSORS, FIBER BRAGG GRATING SENSORS, STRAIN MONITORING
Report Date:
2000 Aug 01
Creation Date:
2001 Oct 17