Abstract:
A method of monitoring a temperature condition includes inputting a light pulse into a fiber optic cable and receiving a reflection signal that arises from said input light pulse in said fiber optic cable. A temperature condition along the fiber optic cable and a location of the temperature condition along the fiber optic cable is determined based on said reflection signal.
Abstract:
The invention relates to an arrangement for detecting an optical signal which enables the light emitted from a curved optical fibre (40) on the long side thereof to be detected. Said arrangement comprises a device (10) for curving the optical fibre (40), a first retaining device (20, 30) for maintaining the optic fibre (40) in its curved state, and a second retaining device (60) for maintaining at least one photodetector (70). The curving device (10) and the second retaining device (60) are displaceable in relation to each other, whereby the photodetector (70) is placed directly on to a predetermined section of the curved optical fibre (40) in an operating state. As a result, the optical path between the fibre section, where the light is emitted from, and the photodetector (70) is minimal.
Abstract:
The invention provides a fiber optic sensing system for use in environments hostile to electronics. The system comprises an optical module comprising a light source and a photodetector, a probe comprising a glass optical fiber core, preferably with a transducer sensitive to the measurement parameter coupled thereto, an extension comprising a plastic optical fiber core, a first connector configured to optically couple the extension to the probe and a second connector configured to optically couple the extension to the optical module. Light emitted from the light source is transmitted to the transducer on the probe and returned to the photodetector by the extension.
Abstract:
A flow rate fiber optic transducer is made self-compensating for both temperature and pressure by using preferably well-matched integral Fabry-Perot sensors symmetrically located around a cantilever-like structure. Common mode rejection signal processing of the outputs allows substantially all effects of both temperature and pressure to be compensated. Additionally, the integral sensors can individually be made insensitive to temperature.
Abstract:
A hand held device is provided which contains at least one light emitting diode (LED) and is useful for the elimination of microorganisms as well as therapeutic treatment by light. A method of treatment and a kit are also disclosed.
Abstract:
Embodiments of the invention provide an improved method and apparatus for sensing position and/or status of an object. For one embodiment, a method generally includes illuminating the object with an optical pulse source and supplying a first optical pulse to a photo-detector, causing a resonant circuit formed by the photo-detector and an inductor to generate a resonant signal. The method also includes supplying at least a second optical pulse to the photo-detector causing a change in the resonant signal, wherein the second optical pulse is reflected from the object, monitoring the change in the resonant signal, and determining a position of the object based on the monitored change in the resonant signal. A velocity, direction of travel and/or acceleration of the object may also be determined from successive position measurements.
Abstract:
An optical characterisation device has a guiding body 200 and a diffractive structure 220 integrated with it. The guiding body 200 delivers radiation to the diffractive structure 220 at a preselected angle and the diffractive structure 220 diffracts at least a portion of radiation guided to it to give spatial resolution according to wavelength. A position sensitive detector 235 detects the position of the spatially resolved radiation and thus the radiation can be characterised according to wavelength. Embodiments of the present invention can be used to monitor and adjust the wavelength of a radiation source, using a feedback connection 135. By using the integrated approach, a very small structure can be realised and the structure can be relatively simply fabricated and assembled. The guiding body 200 might be either capable of supporting multimode propagation of the radiation or might be a single mode waveguide. Where it is capable of supporting multimode propagation, an input to the guiding body 200 acts to select a mode for propagation of the radiation.
Abstract:
Fiber grating environmental measurement systems are comprised of sensors that are configured to respond to changes in moisture or chemical content of the surrounding medium through the action of coatings and plates inducing strain that is measured. These sensors can also be used to monitor the interior of bonds for degradation due to aging, cracking, or chemical attack. Means to multiplex these sensors at high speed and with high sensitivity can be accomplished by using spectral filters placed to correspond to each fiber grating environmental sensor. By forming networks of spectral elements and using wavelength division multiplexing arrays of fiber grating sensors may be processed in a single fiber line allowing distributed high sensitivity, high bandwidth fiber optic grating environmental sensor systems to be realized.
Abstract:
An antenna apparatus detects a reflected light from a scattered light or from a reflector (40) mounted in an optical fiber (6,6a-6d), measures a strain generated in a primary reflecting mirror (1) and so on based on the scattered light or the reflected light, and calculates a reflector surface compensation data based on the strain of the primary reflecting mirror (1) and so on. An antenna driving section (11) is driven according to the reflector surface compensation data in order to compensate a direction of an antenna.
Abstract:
An optical transducer includes a base member, a light source carried on a face of the base member, a light detector carried on the face of the base member laterally spaced from the light source, an optical shield extending from the face of the base member between the light source and light detector, and a displaceable member overlying, and spaced from, the light source, light detector and optical shield, and effective to reflect light from the light source to the light detector. The optical shield includes a transparent plate extending from the face of the base member between the light source and light detector, and carrying a thin layer of a light-blocking material to shield the light detector from direct exposure to the light source. The light source, light detector, and optical shield are all embedded in a transparent plastic potting material. Also described is a method of making such optical transducers by producing an intermediate matrix of a plurality of such light sources, light detectors and optical shields and cutting the matrix into individual optical units.