Heather M Patrick

US Patent:

62496239, Jun 19, 2001

Filed:

Oct 26, 1998

Appl. No.:

9/184465

Inventors:

Heather J. Patrick - Silver Spring MD
Alan D. Kersey - South Glastonbury CT

Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

G02B 626

US Classification:

385 37

Abstract:

A method and apparatus for correcting changes in the mean wavelength of a broadband optical source due to changes in temperature. An optical filter is placed so as to filter the output of source, the filter being selected so that, as a function of temperature, its center wavelength changes as fast or faster than the wavelength centroid of the source.

US Patent:

59456663, Aug 31, 1999

Filed:

May 19, 1997

Appl. No.:

8/858633

Inventors:

Alan D. Kersey - Fairfax Station VA
Heather J. Patrick - Wheaton MD

Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

G02F 1025

US Classification:

25022714

Abstract:

A grating sensor system for simultaneously determining strain and temperature is disclosed, which system comprises: a light source for providing a continuous broadband light; a single mode fiber coupled to the light source; a hybrid fiber grating sensor written into the single mode fiber, the sensor comprised of a long period grating having a first center wavelength and first and second fiber Bragg gratings respectively having second and third center wavelengths for respectively reflecting light therefrom at about the second and third center wavelengths, with the first center wavelength being between the second and third center wavelengths, the long period grating producing a broadband power loss around its first center wavelength, the first center wavelength shifting with strain and temperature, the sensor measuring the effect of the long period grating wavelength shift on the relative intensities of the light reflected from around the second and third wavelengths; an optical analyzer responsive to the reflected light signals from the hybrid fiber grating sensor for measuring the wavelengths and intensities in the reflected light signals; and a circuit responsive to the measured wavelengths and intensities of light from the optical analyzer for simultaneously calculating the strain and temperature being sensed by the sensor.