Tapered optical fiber sensor

Apparatus for measuring a physical effect, comprising:

• a single-mode optical fiber for transmitting light of a given wavelength therethrough and having a narrow waist region along the length thereof, said narrow waist region having a Vco parameter of less than one;
• means for launching light of the given wavelength into the core of said optical fiber;
• means for measuring the intensity of light exiting from the core of said optical fiber;
• and
• means for bending the fiber in the narrow waist region in response to the physical effect to be measured.

Apparatus for measuring a change in pressure, comprising:

• a single-mode optical fiber for transmitting light of a given wavelength therethrough and having a core, two ends, and a narrow waist region along the length thereof, said narrow waist region having a Vco parameter of less than one;
• means for launching light of the given wavelength into one end of the core of said optical fiber;
• means for measuring the intensity of light received from the other end of the core of said optical fiber;
• and
• bellows means for causing displacement in response to pressure change operatively connected so that the displacement bends said optical fiber at the narrow waist region.

A method for measuring a change in pressure, comprising the steps of:

• launching light of a given wavelength into one end of the core of a single-mode optical fiber having a narrow waist region along the length thereof, said narrow waist region having a Vco parameter of less than one;
• positioning the fiber so that a change in pressure bends the fiber in the narrow waist region;
• measuring the intensity of the light exiting from the other end of the core of the fiber;
• and
• determining the pressure change in accordance with the measured intensity.