Abstract: A system adapted for attachment to a device that undergoes changes in temperature and pressure, and for detecting changes in temperature and pressure in the device comprises a mechanism for attaching the system to the device and an optic device that includes pressure-responsive, temperature-responsive optical fibers that produce signals representative of temperature changes over a first optical frequency band, and of pressure changes over a second, distinctly different optical frequency band, or two or more optic devices, at least one including a pressure-responsive optical fiber, and at least one including a temperature-responsive optical fiber.

Abstract: A fiber optic fuel or liquid level gauge is disclosed which determines the liquid level by measuring the amount of light loss due to evanescent transfer to the fuel or liquid. An optical fiber is supported in the fuel or liquid tank, with a first end adjacent the highest possible liquid level to be measured with a reflector at the first end. The optical fiber extends downwardly through the tank, and its second end is connected to a light source for injecting light into the fiber. The intensity of the input light is compared to the intensity of light reflected from the first fiber end, and the liquid level is calculated from the light loss. The gauge has very high reliability since it has no moving mechanical parts.

Abstract: A shaft rotation rate sensor for turbine engines. A reflective radial grating on the surface of the turbine shaft is employed in conjunction with an electromagnetic wave source and beam combining elements to mix two beams of frequency f and f.+-..DELTA.f, where .DELTA.f is proportional to the rotation rate of the grating. The source energy is reflected off the grating, and the zero-th and first order transmission from the grating are mixed to give the beat frequency proportional to the rotation rate. The sensor has no moving parts.

Abstract: A speed sensor for a moving vehicle. A transmissive grating is used in conjunction with an electromagnetic wave source and beam combining waveguide to mix two beams of frequency f and f+.DELTA.f, where .DELTA.f is proportional to the speed of the grating relative to the ground. The source energy is reflected off the road to the grating. The zeroth and first order transmission from the grating are mixed to give the beat frequency .DELTA.f proportional to the ground speed. The sensor has no moving parts, and is independent of any gear ratios.

Abstract: Latent fingerprints are detected by upconverting infrared radiation provided by a special dusting powder and digitally imaging the upconverted radiation. In accordance with the principles of the present invention, a real time image of latent fingerprints is obtained by first "dusting" the print with a powdered upconversion material. The print is then illuminated with 1.55 .mu.m infrared radiation using a fiber optic bundle in the form of a probe. The 1.55 .mu.m infrared radiation is converted into several reradiated wavelength bands by the powdered upconversion material. A charge coupled device or diode matrix detector array converts the image of the fingerprint to digital format for real time display and/or transmission over airwaves. The system is a portable latent fingerprint acquisition system that permits rapid fingerprint evaluation and comparison. A method of detecting fingerprints is also disclosed.

Abstract: A fiber optic fuel or liquid level gauge is disclosed which determines the liquid level by measuring the amount of light loss due to evanescent transfer to the fuel or liquid. An optical fiber is supported in the fuel or liquid tank, with a first end adjacent the highest possible liquid level to be measured with a reflector at the first end. The optical fiber extends downwardly through the tank, and its second end is connected to a light source for injecting light into the fiber. The intensity of the input light is compared to the intensity of light reflected from the first fiber end, and the liquid level is calculated from the light loss. The gauge has very high reliability since it has no moving mechanical parts.

Abstract: A precision liquid leak detector 10 free of mechanical moving parts is disclosed herein. The liquid leak detector 10 of the present invention is disposed to measure the rate of change of the volume of a liquid within a container 14. The leak detector 10 includes a light guide 16, implemented as an optical fiber, which is disposed within the container 14 and at least partially immersed in the liquid. The optical fiber 16 includes a fiber core circumscribed by a fiber cladding selected such that evanescent wave loss occurs as a result of immersion of the cladding within the liquid. The optical fiber 16 is positioned in optical alignment with a laser source 26, which injects optical energy therein. The leak detector 10 of the present invention further includes an arrangement 24 for measuring the decrease in the intensity of the injected optical energy occurring over a length of the fiber 16 immersed in the liquid.

Abstract: A fiber-optic interferometric chemical sensor for detecting chemical vapors in the air. The chemical sensor 10 includes a light source 12 which outputs an optical signal to a first beam splitter 14. The first beam splitter 14 splits the optical signal into first and second components and transfers the optical signal over sensor and reference optical fibers 20 and 22 respectively. The optical fibers 20 and 22 are bonded to the sensor and reference magnetostrictive substrates 24 and 26, which oscillate in response to an oscillating electromagnetic field generated by a coil 28 circumscribing the substrates 24 and 26. The sensor substrate 24 is further coated with a substance to facilitate collection thereon of molecules associated with the chemical vapor being detected. The optical outputs of the optical fibers bonded to the substrates 24 and 26 are then output to second and third beam splitters 16 and 18 respectively, and first and second beam combiners 32 and 34 respectively.