USA As Represented by Secretary of the Navy

Barbara J White

Lloyd C Bobb

Jon P Davis

Arthur Samouris

A physical property of a fluid or of any optical fiber is measured using an ptical fiber interferometer. A conductive material is disposed upon the surface of a region of a light tranmitting optical fiber and the region having the conductive material is disposed in the fluid. Light energy is applied to one end of the fiber and transmitted light is received at the other end of the fiber. Electrical energy is applied to the conductive material disposed upon the surface of the fiber to heat the region of the fiber and cause a change in the optical path length of the light transmitted through the fiber. The physical property of the fluid or optical fiber is determined in accordance with the change in the optical path length or phase of the received light caused by applying the electrical energy to the conductive material. Thermal conductivity is measured using a series of short energy pulses and determining the average phase change. The flow rate of a fluid is measured by measuring the phase change and applied electrical energy upon heating the fiber to an equilibrium temperature. The conductive material is gold and it encircles the fiber. The gold may be disposed on the jacket of the fiber or the jacket may be removed before disposing the gold.

Optical fiber sensor for measuring physical properties of fluids

A physical property of a liquid or of any optical fiber is measured using optical fiber interferometer. A conductive material is disposed upon the surface of a region of a light transmitting optical fiber and the region having the conductive material is disposed in the liquid. Light energy is applied to one end of the fiber and transmitted light is received at the other end of the fiber. Electrical energy is applied to the conductive material disposed upon the surface of the fiber to heat the region of the fiber and cause a change in the optical path length of the light transmitted through the fiber. The physical property of the liquid or optical fiber is determined in accordance with the change in the optical path length of the received light caused by applying the electrical energy to the conductive material. A series of short energy pulses is provided and the average phase change is determined. The conductive material is gold and it encircles the fiber. The gold may be disposed on the jacket of the fiber or the jacket may be removed before disposing the gold.

Optical fiber sensor for measuring physical properties of liquids

The phase of light passing through an optical waveguide is modulated by aying electric current to heat the waveguide and thereby alter the length and refractive index thereof. An application for the thermal phase modulation concept is provided in a Mach-Zehnder interferometer.

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Hatboro, PA, United States of America

Barbara J White