Abstract: A fiber optic thermometer has a hollow body made of material of low thermal expansion and an optical fiber supported by a high thermal expansion intermediate support to form a cantilever section, a fiber optic splitter coupled to a first end of the optical fiber and a light source for directing light into the optical fiber via one branch of the optical splitter. A photodetector receives light conveyed through the optical fiber via the other branch of the optical splitter and measures intensity of the received light. A reflective target supported at a second end of the hollow body is axially aligned with the second end of the optical fiber at room temperature. Upon ambient temperature changes the cantilever section moves relative to the reflective target thereby changing the instantaneous intensity of light reflected by the target into the second end of the optical fiber and measured by the photodetector.

Abstract: A reflective element for directing an optical signal into a fiber optic sensor having an optical fiber includes a plane containing a sharply defined straight line that separates between a first area of low reflectivity and a second area of high reflectivity. The plane is disposed parallel to a free end surface of the optical fiber so that the free end surface intersects the line of the reflective element, whereby relative movement between the free end surface of the optical fiber and the line in response to a physical change sensed by the fiber optic sensor induces variations in an optical signal reflected by the reflective element through the optical fiber, which variations allow measurement of the physical change.

Abstract: A reflective element for directing an optical signal into a fiber optic sensor having an optical fiber includes a plane containing a sharply defined straight line that separates between a first area of low reflectivity and a second area of high reflectivity. The plane is disposed parallel to a free end surface of the optical fiber so that the free end surface intersects the line of the reflective element, whereby relative movement between the free end surface of the optical fiber and the line in response to a physical change sensed by the fiber optic sensor induces variations in an optical signal reflected by the reflective element through the optical fiber, which variations allow measurement of the physical change.

Abstract: A reflective element for directing an optical signal into a fiber optic sensor having an optical fiber includes a plane containing a sharply defined straight line that separates between a first area of low reflectivity and a second area of high reflectivity. The plane is disposed parallel to a free end surface of the optical fiber so that the free end surface intersects the line of the reflective element, whereby relative movement between the free end surface of the optical fiber and the line in response to a physical change sensed by the fiber optic sensor induces variations in an optical signal reflected by the reflective element through the optical fiber, which variations allow measurement of the physical change.

Abstract: A fiber optic accelerometer has a hollow body that supports an optical fiber therein so as to form a cantilever section, a fiber optic splitter coupled to a first end of the optical fiber and a light source for directing light into the optical fiber via a first branch of the optical splitter. A photo detector receives light conveyed through the optical fiber via a second branch of the optical splitter and measures an intensity of the received light. A reflective target supported at a second end of the hollow body is axially aligned with the second end of the optical fiber in the absence of force. Upon acceleration the cantilever section moves such that its position relative to the reflective target changes thereby reducing the instantaneous intensity of light reflected by the target into the second end of the optical fiber and measured by the photo detector.

Abstract: An arrangement for a fiber optic microphone having at least one pair of optical fibers, each having an input end portion and an output end portion made of a material having a critical refractive angle ?crit and having a numerical aperture NA. The input end portion of a first fiber is connectable to a source of light and the output end portion of a second fiber is connectable to a photoelectrical transducer. Both end portions have an inner diameter, an axis and a rim. The input and output end portions are mutually affixed along a single plane with their rims touching each other at a point, the axes forming an angle ? therebetween. The rims are cut with respect to the axis, at an angle in a plane perpendicular to the single plane and to a bisector of angle ? at the point, where ?=2×?crit?NA.

Abstract: An arrangement for a fiber optic microphone having at least one pair of optical fibers, each having an input end portion and an output end portion made of a material having a critical refractive angle ?crit and having a numerical aperture NA. The input end portion of a first fiber is connectable to a source of light and the output end portion of a second fiber is connectable to a photoelectrical transducer. Both end portions have an inner diameter, an axis and a rim. The input and output end portions are mutually affixed along a single plane with their rims touching each other at a point, the axes forming an angle ? therebetween. The rims are cut with respect to the axis, at an angle in a plane perpendicular to the single plane and to a bisector of angle ? at the point, where ?=2×?crit?NA.