Abstract: A high temperature, short time microwave heating system 10 for heat-sensitive liquid material to inactivate or reduce pathogenic agents or organisms, such as viral contaminants. The system 10 includes a disposable cartridge 26 consisting of a preheater 32, a microwave heating coil 56 and cooler 58 with the heating coil 56 adapted to be easily inserted in and removed from the microwave heating field.

Abstract: A new and improved inner tip or head is provided for a fiberoptic scanner mechanism of the type monitoring the presence of flame in a boiler furnace. The scanner tip according to the present invention is more easily installed and removed. It also reduces the transfer of heat from the furnace to the fiberoptic scanner.

Abstract: The purpose of the present invention is to provide a time domain reflectometer in which the system cost is low and the dynamic range is wide. In accordance with the present invention, an excitation light source for generating continuous light of a predetermined frequency (e. g., 1.48 .mu.m), and a ring laser part for generating a high power light pulse in accordance with the continuous light are provided. A light branch device is held in common by the ring laser part and a measurement part. The light branch device makes the light pulse which has been incident on one of its end parts to be incident on a light cable to be measured; and the light branch device also receives response light and supplies the response light to a light receptor in the measurement part. In the measurement part, the response light is converted to a corresponding electric signal and the signal is amplified to be supplied to a measurement circuit.

Abstract: An interferometric temperature sensing system provides a simplified design for accurately processing an interference fringe pattern using self coupling effects of a laser detection element, where a laser diode and an optical detection element are combined in one package. Accordingly, the present invention is easily made and the measurement of temperatures within a wide range can be easily performed.

Abstract: Respective SiC (silicon carbide) photodiode sensors are used to measure flame temperature at each cylinder of an internal combustion engine, and information generated by the SiC photodiode sensors is used to control the fuel injection in a feedback loop to control individual cylinder flame temperature and combustion.

Abstract: A temperature distribution measuring apparatus, which inputs pulsed-light into an optical fiber, measures backward Raman-scattered light generated in the optical fiber, and calculates a temperature distribution along the optical fiber in accordance with the ratio of the intensity of anti-Stokes' light to the intensity of Stokes' light of the backward Raman-scattered light.

Abstract: A light receiving section of an optical pyrometer enables accurate temperature measurement of molten metal with minimum cost. The light receiving section of the optical pyrometer comprises a cylindrical member 1 made of a paper sleeve 2 with a quartz cap 4 sealed to the front end of the paper sleeve 2 using refractory material 3. An open end of the quartz cap 4 is oriented outwardly with respect to the cylindrical member 1 while the closed end 41 of the quartz cap 4 provides a light transmission window for transmitting radiant rays from the molten metal 24 to the optical pyrometer 21.

Abstract: In accordance with the present invention, a pyrometer adapter is disclosed for providing the optical head of a pyrometer access to a target area in a gas turbine engine, where the pyrometer adapter is subjected to relative motion between a first mounting surface and a second mounting surface, the pyrometer adapter including an outer tube having a first end mounted to the first mounting surface of the gas turbine engine and a second end terminating in a flange, and a second tube positioned radially inward of and in concentric arrangement with the outer tube, wherein the second tube extends through an opening in the first mounting surface so that the second tube is mounted at its first end to the gas turbine engine at the second mounting surface adjacent the target area and the pyrometer optical head is attached to a second end of the second tube, where the second tube also includes a flange extending from a middle portion thereof which is attached to the flange of the outer tube to form a flexible diaphragm wh

Abstract: An optical method and apparatus for measuring the temperature of a substrate material with a temperature dependent bandgap. The substrate is illuminated with a broad spectrum lamp and the bandgap is determined from the spectrum of the diffusely scattered light. The spectrum of the light from the lamp is sufficiently broad that it covers the spectral range above and below the bandgap of the substrate. Wavelengths corresponding to photon energies less than the bandgap of the substrate are transmitted through the substrate and are reflected from the back surface of the substrate as well as from the front surface while the wavelengths corresponding to photon energies larger than the bandgap are reflected only from the front surface. If the front surface is polished the front surface reflection will be specular while if the back surface is rough the reflection from the back surface will be non-specular. The back surface reflection is detected with a detector in a non-specular location.

Abstract: An optical interferometer comprises a multi-mode sapphire fiber as a high temperature sensor. One end of the sapphire fiber is coupled to a silica fiber and, in turn, to the sapphire fiber. The sapphire fiber sensor produces reference and sensor reflections that produce optical fringes at the output of a detector coupled to the silica optical fiber via an opto-coupler. The optical fringes are related to displacements of the sensor which, in turn, can provide an indirect measurement of pressure, strain or temperature of the surface.

Abstract: The invention is drawn to methods and devices for measuring temperature with a simple probe, a single interrogating light source and a single photodetector in a manner that the same probe can be used for simultaneously sensing another physical parameter, using the same interrogating light source and the same photodetector. The invention also allows the use of a single probe for measuring temperature in two independent physical modes, using a single interrogating light source and a single photodetector. In a preferred embodiment the probe includes a photoluminescent material having a luminescence decay time which decreases substantially with increasing temperature over a temperature range within which its luminescence quantum efficiency remains approximately constant or varies only minimally.

Abstract: A method and apparatus for measuring temperature by subjecting, to the temperature to be measured, a light-transmissive body of a material whose dimensions change in response to temperature, directing first rays of light from a light source through a first path including a predetermined distance of travel through the light-transmissive body, simultaneously directing second rays of light from the light source through a second path, parallel to the first path and of a linear length equal to that of the first path, but not including the predetermined distance of travel through the light transmissive body, and measuring the change in phases between the first and second light rays at the ends of the first and second paths, to thereby provide a measurement of the temperature to which the light-transmissive body was subjected.

Abstract: A concentration correcting apparatus comprising a correction coefficient calculating means and a correcting means is shown and described. The correction coefficient calculating means calculates a correction coefficient for correcting the concentration of the material when the actual density of the medium at the measurement of the material is calculated in terms of the density of the medium under the reference temperature and pressure, from the results of the temperature measuring means and the pressure measuring means. The correcting means corrects the results of the material measuring means to a concentration under the reference temperature and pressure on the basis of the correction coefficient.

Abstract: An apparatus for measuring temperature along an optical fiber uses backscattered light and optical time domain reflectometry to obtain a measure of the temperature distribution along the fiber. The ratio of anti-Stokes Raman to Stokes Raman backscattered light is used to determine the temperature distribution. In order to compensate for fluctuations in the wavelength of a laser source there is provided in a first embodiment an optical filter which passes Fresnel components of the light reflected from a distal end of the fiber. Changes in the ratio of the filtered Fresnel components correspond to changes in the source wavelength which may then be compensated by adjusting the source wavelength. In a second embodiment, the optical filter is used to measure the ratio of anti-Stokes Raman and Stokes Raman backscattered components derived from a reference temperature section of the fiber in which the temperature is held constant.

Abstract: A sensor for use in an optical temperature detector system having a birefringent element made of a single crystal metal oxide plate. A broad band light spectrum is transmitted through a first linear polarizing element to create a linearly polarized wave. The linearly polarized wave on passing through the single crystal metal oxide plate decomposes into first and second orthogonally polarized waves. Propagation of the linearly polarized wave through the birefringent single crystal metal oxide plate introduces a temperature dependent phase shift between the two waves. Thereafter, a second linear polarizer combines the first and second orthogonally polarized waves to create a modulated light spectrum having a fringe pattern, the fringe pattern being a function of the current temperature experienced by said birefringent element.

Abstract: The invention is drawn to methods and devices for measuring temperature with a simple probe, a single interrogating light source and a single photodetector in a manner that the same probe can be used for simultaneously sensing another physical parameter, using the same interrogating light source and the same photodetector. The invention also allows the use of a single probe for measuring temperature in two independent physical modes, using a single interrogating light source and a single photodetector. In a preferred embodiment the probe includes a photoluminescent material having a luminescence decay time which decreases substantially with increasing temperature over a temperature range within which its luminescence quantum efficiency remains approximately constant or varies only minimally.

Abstract: A temperature distribution analyzer is disclosed. In the analyzer, a measuring optical fiber is provided so as to extend through a target region in order to analyze the temperature distribution of the region. A LD pumped solid state laser generates pulse light having high energy and supplies the pulse light to one of the terminal portions of an optical fiber. This causes a stimulated-Raman-scattering phenomenon in the optical fiber whereby Raman-scattered light is obtained from the other terminal portion of the excitation optical fiber. An optical filter selects light having a predetermined wavelength from the Raman-scattered light and outputs the selected light. An optical device introduces the output light of the optical filter to one of the terminal portions of the measuring optical fiber and receives Raman-backscattered light generated in the measuring optical fiber through the same terminal portion. A photodetector converts the Raman-backscattered light to an electrical signal.

Abstract: A thermal dilation type optical flow sensor includes an optical heating sce for heating a flowing fluid and a sensor disposed in a downstream direction from said heating source wherein the sensor includes a probe for varying a reflected light according to the temperature of the probe, a Michelson type interferometer for measuring the temperature of the probe according to the phase of the reflected light, and a calculating device for determining the flow rate based on the temperature of the probe, the distance between the heating source and the probe, and the amount of heat produced by the heating source. In an alternative embodiment, a thermal dilation type optical flow sensor includes a reflecting probe disposed in a flowing fluid for reflecting an incident light with a phase varied according to the probe temperature, an optical heater for heating the probe with a predetermined heat, and a calculating device for calculating a flow rate based on the predetermined heat and the phase of the reflected light.

Abstract: A sweeping photoreflectance spectroscopy technique and apparatus is disclosed. This technique and apparatus enable the determination of the band structure of semi conductors and other materials at low temperatures by the mechanism of modulating the photoreflectance signal in a predetermined manner thereby enabling its detection in the presence of a much larger, but continuous, undesirable photoluminescence signal.

Abstract: A plurality of current detectors are provided in a plurality of prescribed spots of a transmission line for locating a fault caused, e.g. by lightning. A plurality of discriminators are provided in correspondence to the plurality of current detectors. Each discriminator receives detected signals from an arbitrary pair of the plurality of current detectors for detecting a relative difference between arrival times of the detected signals while extracting low-frequency components from the detected signals respectively and for detecting a phase difference between the extracted low-frequency components. A locator receives relative time difference data and phase difference data from the plurality of discriminators, to locate a faulty point in the transmission line on the basis of the received data.

Abstract: A temperature-measuring method comprises inputing laser pulses into an optical fiber to be measured and measuring temperature distribution in the fiber from the ratio of the amplitudes and the delay time of Stokes light and anti-Stokes light contained in the return beam from the optical fiber, wherein the temperature distribution is measured by using equations: ##EQU1## where T(x) is temperature to be measured, .THETA. is the reference temperature, R' (T) is the relative ratio of amplitude at the measuring point, R' (.THETA.) is the relative ratio of amplitude at the reference temperature point, k is Boltzmann's constant, h is Planck's constant, c is velocity of light, .nu. is Raman shift, .alpha. is distance, wherein the attenuation difference .alpha. is represented by a function .alpha.{T(.tau.)} dependent on temperature T(.tau.) at the measuring point .tau., and the exponential function in which the exponential part is represented by a value obtained by integrating the function .alpha.{T(.tau.

Abstract: A device for the measurement of a temperature in a relatively low range having the lower limit of below 100.degree. C. is proposed. The device is suitably used for measuring a temperature of a substrate 4 during a sputtering treatment in a vacuum environment. Infrared rays radiated from the substrate 4 in a vacuum chamber 1 are collected by an optical lens 13 mounted in a freely movable probe 10 via a mirror (15) provided in a hood 14 attached to a front end of the probe (10) for deflecting the incident rays to the lens 13. The collected rays are led outside the chamber 1 to a sensor through a fluoride fiber 8 optically connected to the lens 13. The fiber 8 is enveloped in an air-tight manner within a metal bellows 9.

Abstract: The invention is drawn to methods and devices which allow the simultaneous optical measurement of temperature and another physical parameter using a single probe, a single interrogating light source and a single photodetector. The invention also allows the use of a single probe for meausring temperature in two independent physical modes, using a single interrogating light source and a single photodetector. The single probe includes a photoluminescent material having luminescent centers which when excited with transient interrogating light of a wavelength within a predetermined spectral range emit luminescence light from two excited electronic energy levels, one of them being higher than the other and having a higher rate of luminescence decay than the other level, and wherein the relative intensities of the luminescence light emitted from each of the two excited energy levels vary as a function of the probe temperature.

Abstract: A pulsed laser system for visually detecting faults in optical waveguides. A laser operating at a duty cycle of less than fifty percent (50%) produces visible light pulses at a frequency sufficiently high as to visually appear to be continuous. The laser is coupled to an optical waveguide by a connector. Faults are located due to a visible glow at a defective point on the waveguide.

Abstract: A temperature-measuring method which comprises inputting laser pulses into an optical fiber to be measured and measuring the temperature distribution in the fiber from the ratio of the amplitudes and the delay time of the Stokes light and the anti-Stokes light contained in the return beam from the optical fiber, wherein the temperature distribution is measured by using an equation: ##EQU1## where T(x) is the temperature to be measured, .THETA. is the reference temperature, R'(T) is the relative ratio of amplitude to the measuring point, R'(.THETA.) is the relative ratio of amplitude at the reference temperature point, k is the Boltzmann's constant, h is the Planck's constant, c is the velocity of light, .nu. is the Raman shift, .alpha. is the attenuation difference in the optical fiber between the Stokes light and the anti-Stokes light, and x is the distance, wherein the attenuation differenct .alpha. is represented by a function .alpha.{T(.tau.)} which is dependent on the temperature T(.tau.

Abstract: This invention relates to a method and apparatus, i.e. a "wavelength meter", for determininhg the wavelength of optical radiation, e.g., visible radiation. Radiation is subjected to two or more wavelength dependent phase modulations having a net effect which is wavelength dependent and is zero at a predetermined wavelength. The net modulation is then determined so as to obtain the difference between the predetermined wavelength and the actual wavelength of the radiation.

Abstract: An improved apparatus and means for measuring temperatures inside enclosures or conduits containing hot gases laden with entrained solids using a pyrometer. The improvement involves an optical access port consisting of a high strength sight tube, a safety valve, a double sight glass, various purge connections and provisions for optical alignment. A dynamic purge system keeps the optical sight path clear during normal operation, and clears the path if it begins to become occluded during operational upsets within the enclosure or conduit. The improved optical access port is mounted on the exterior wall of the vessel or conduit.

Abstract: A radiation pulse generating assembly comprises a radiation generator such as a laser for generating pulses of radiation having pulse widths in the order of pico seconds. The pulses from the generator are coupled onto an optical fiber which causes the pulses to undergo Raman scattering to generate reduced width pulses with wavelengths lying within a Raman spectrum and having widths in the order of femto seconds. A first filter filters out the initial pump wavelength while a second filter downstream of the first filter is tunable to select reduced width pulses within a desired wavelength band.

Abstract: A method of measuring temperature comprises the steps of consecutively launching (1, 2) input pulses of light at two different wavelengths into a temperature sensing element in the form of an elongate optical fibre (3); passing Raman scattered light from said element and deriving from said input pulses to intensity detectors (7, 8); obtaining from the detectors (7, 8) output signals indicative of the intensity of the Raman scattered light; and processing said output signals to provide a temperature measurement. A known position (10) along the optical fibre (3) is maintained at a known temperature to provide a reference for deriving temperature measurements at other positions along the optical fibre.

Abstract: An optical time-domain reflectometry method of sensing respective values of a physical parameter, such as temperature, at different locations along an optical fibre, in which back-scattered optical radiation is used to produce output signals indicative of the values being sensed, is improved by employing optical filtering means to ensure that the back-scattered radiation used is restricted to a preselected single spectral line resulting from inelastic scattering in the fibre, for example one of the Anti-Stokes Raman lines, or to two mutually adjacent such lines.

Abstract: A measuring apparatus for space-resolved temperature measurement by optical backscattering measurement at optical waveguides, wherein an improvement in the signal-to-noise ratio is achieved by including an additional filter device to attenuate the Rayleigh peak in the backscattered light. The filter device preferably includes a polarizing beam splitter, behind which a quarter-wave plate and an interference filter are disposed in the transmission direction.

Abstract: An optical pyrometer for a gas-trubine engine has a radiation receiving head located to view the blades of the engine and supply radiation from the blades to one end of a fibre-optic cable. At the other end of the cable there is mounted a detector comprising a cylindrical metal casing containing a photodiode and a signal conditioning circuit that amplifies the photodiode output. The output circuit is supplied to an electrical connector mounted on the casing. The detector can be mounted directly on the casing of a processing unit by mating its connector with an electrical connector fixed on the processing unit casing thereby avoiding the need for cables between the two casings. The connector on the detector has a flange that provides good thermal contact with the connector on the processing unit so as to help equalize the temperatures of the two casings. The processingunit casing is cooled by means of a thermal transfer unit supplied with liquid fuel.

Abstract: Apparatus and method for optically measuring temperature by spectroscopically determining the temperature-induced changes in the wavelength spectrum of light interacting with a semiconductor temperature sensor. The method includes providing illumination from a radiant energy source with a broad wavelength spectrum, guiding the radiant energy to a remote semiconductor sensor, returning the radiant energy after interaction with the semiconductor sensor, and analyzing the returned wavelength spectrum to determine the temperature-induced spectral changes due to the absorption edge of the semiconductor sensor. One embodiment of the invention comprises a quartz-halogen lamp, an optical multiplexer, optical fiber lightguides, a gallium arsenide semiconductor sensor, a fast scan spectrometer, an analog to digital converter and a microprocessor for processing the information of the returned wavelength spectrum for determining and displaying the sensor temperature.

Abstract: A portable temperature data recorder for temporarily storing plural sets of temperature data representative of temperatures at a single location or at different locations, and automatically transferring the stored temperature data to a data processing unit. The portable recorder has a connector for connection thereof to the data processing unit. The portable recorder may further have a connector for connection thereof to a stationary temperature detector or thermometer installed at each measurement location. Alternatively, the temperature recorder incorporate a temperature detector for measuring the temperatures at the measurement locations. A clock circuit may be provided in the portable recorder, so that the temperature data may be stored together with measurement time data. The temperature detector may be a radiation thermometer provided at the measurement location, or built in the portable recorder.

Abstract: Temperature is measured by launching pulses of light into an elongate optical fibre and determining the temperature at positions along the fibre from the intensity of light scattered at those positions. The input pulses can have either the same or two different wavelengths, and the scattered light can be either Raman or Brillouin scattered and either forward scattered or backscattered. One position along the fibre can be maintained at a known temperature in order to provide a reference for other calculations. In particular embodiments the temperature is derived from the ratio between the intensities at two anti-Stokes wavenumber shifts or between an anti-Stokes scattered and a Rayleigh scattered intensity measurement. Otherwise the intensities of Stokes and anti-Stokes shifted Brillouin back scattered light can be used to derive the temperature.

Abstract: A temperature sensor comprises a single-mode all-fiber Michelson interferometer. The interferometer includes a bi-directional coupler and signal and reference fibers having mirrored ends. These two fibers are of unequal lengths to provide an optical path length in-balance and the signal fiber may have a metal temperature sensing probe at its mirrored end. The injection current of a laser light source for the interferometer is modulated with a ramping signal so that a linearly moving interference pattern is produced at the output by mixing of the reflected beams propagated in the signal and reference fibers.

Abstract: A fluorescent material arranged under an environment of temperature objective for measurement is excited by irradiating red color light or infrared rays, then fluorescent light generated from the fluorescent material is received by an optical sensor thus the temperature of the fluorescent material is measured from an output of the optical sensor on the basis of the correlation between a fluorescent characteristic of the fluorescent material and temperature.

Abstract: A temperature detecting device employing as a temperature detecting element a CdInGaS.sub.4 compound semiconductor material. The temperature of a body in thermal contact with the temperature detecting element is determined using either a reflecting or an absorbing technique. CdInGaS.sub.4 semiconductor material used as a light detecting element provides a temperature measuring range of about -200.degree. C. to about 400.degree. C.

Abstract: A method of measuring the temperature in a high pressure furnace of a hot isostatic pressing apparatus, wherein a closed-end pipe having its inside communicated with the inside of the high pressure furnace and enabling a pressure medium to pass therethrough is disposed in the furnace, an incident top end of an optical fiber, a bundle of optical fibers or like other equivalent optical rod-like memeber is disposed to the open end of the closed-end pipe so as to be capable of receiving thermally radiated light from the inside of the closed-ended pipe and an exit rear end thereof is led out through a cover and to the outside of said high pressure vessel and a measuring system is connected to said exit rear end to detect heat radiation power from the top end of the closed-end pipe to thereby measure the temperature inside of the furnace.

Abstract: A pyrometer for viewing the blades of an engine has a forward lens which produces a first image of the blades in an image plane P.sub.1. Rearwardly of the image plane P.sub.1 is an assymetric faceted lens assembly having a central region with a long focal length, and an outer annular region of shorter focal length. The outer region of the rear lens assembly forms a second image of the first image in a second image plane P.sub.2. The inner region forms a third image of the forward surface of the first lens in the second image plane P.sub.2. A disc mask is fixed centrally to the forward surface of the first lens, and an annular mask is located in the first image plane P.sub.1. The forward end of a fibre-optic cable is located in the second image plane P.sub.2 and comprises a central bundle of fibres which receives the second image, and two outer bundles which receive different parts of the third image.

Abstract: A slight tube assembly, in combination with a sensing instrument, such as an optical pyrometer, for use in continuously monitoring the temperature of the first row of rotating blades in large gas turbines, particularly the type used in industry. Temperature data received by the pyrometer unit is fed to a control circuit, which regulates fuel input to the tubine to control the firing temperature. The key to obtaining reliable blade temperature data in the practice of this invention is the position of the sight tube in the turbine, which enables the pyrometer to "view" the rotating blades along a direct line of sight that penetrates a hot gas duct, but not the turbine section of the engine.

Abstract: To measure the heat transfer coefficient of a sample, an element with temperature sensitive optical properties is placed in contact or implanted in the sample. The element is heated or cooled. The temperature difference between the element and the unheated sample and the rate of heating or cooling indicate the heat transfer coefficient of the sample. In one embodiment, the element is heated or cooled at a constant rate. The heat transfer coefficient of the sample is then inversely related to the difference in temperature between the element and the unheated sample. Alternatively, the element may be heated or cooled at such a rate that the temperature difference between the element and the unheated sample remains substantially constant. The heat transfer coefficient of the sample then varies directly with the rate of heating or cooling. The heat transfer coefficient of a sample is a measure of its composition and other physical properties.

Abstract: In an optical fiber type temperature detector using temperature change of refraction index in birefringent crystal, by using LiTaO.sub.3 or Sr.sub.x Ba.sub.l-x Nb.sub.2 O.sub.6 single crystal (0.5<x<1.0) as material (13) for sensor and quartz as material for setting temperature range, a high sensitive and highly stable temperature detector using light emitting diode as light source is realized. Furthermore, as configuration of sensor part, miniaturization and light weight is devised by disposing rutile (11) or calcite between optical fibers (8, 9) and rod lens (12) to make polarization separation.

Abstract: To be of most use as an input signal for the control system of a gas turbine aeroengine, a pyrometer-derived turbine blade temperature signal should represent the average temperature of the hottest parts of the blades with fast and accurate response when the average temperature of the hottest parts changes with engine conditions. The invention achieves this by providing the pyrometer with an optical system adapted to give the pyrometer's photo-diode a large field of view which is rectangular at the face of the turbine rotor and which extends an integer number of inter-blade passage widths in the circumferential direction and a portion of the length of the blade aerofoils in the radial direction.

Abstract: In a radiation pyrometer in a gas turbine engine, non-uniformly distributed changes in transparency of an optical element in the system, e.g. contamination of pyrometer objective lens L.sub.1 by combustion products from the turbine can be automatically detected. Lens L.sub.1 focusses radiation from target T onto an additional lens L.sub.2, which in turn focusses it onto the end E of the fibre-optic bundle F. Considered reciprocally, lens L.sub.2 images the end E of fibre-optic F into L.sub.1, so that although each optical fibre in end E receives radiation from all parts of target T, each fibre is imaged into a corresponding discrete area of L.sub.1. Fibre-optic bundle F comprises two (or more) sub-bundles F.sub.1 and F.sub.2 forming complementary sub-areas of end E and each sub-bundle is provided with its own photodetector P.sub.1, P.sub.2 and associated pre-amplifier A.sub.1,A.sub.2 adjusted so that their outputs A.sub.1 S.sub.1 and A.sub.2,S.sub.2 are matched at the non-contamination condition.

Abstract: Method and apparatus are provided for measuring temperature and for generating optical signals related to temperature. Light from a fiber optic is directed to a material whose fluorescent response varies with ambient temperature. The same fiber optic delivering the excitation beam also collects a portion of the fluorescent emission for analysis. Signal collection efficiency of the fiber optic is enhanced by requiring that the fluorescent probe material be in the shape of an oblong parabolically tapered solid. Reproducibility is enhanced by using Raman backscatter to monitor excitation beam fluctuations, and by using measurements of fluorescence lifetime.

Abstract: A composite material having high mechanical strength and optical transmission capabilities may be adapted for use in aircraft structural body elements, lighting displays, and other environments where light transmitting and receiving systems are located in physical proximity with a structural component. The disclosed material eliminates the need for separate retention structures for optical fibers.

Abstract: The light guide and the method of measuring temperature with the aid of said light guide relate to optical pyrometry of melts.A light guide 1 is made from a light-permeable refractory corrosion-resistant material such as leucosapphire, for example, and according to the invention comprises 2 portions: a narrow portion 2 in the form of a rod, and a large portion 3 with a flat end 3a being an operating end of the light guide 1. The large portion 3 of the light guide 1 represents with respect to the narrow portion 2 an optical cavity producing radiation of the operating end 3a substantially in the form of a radiation of an absolutely black body. The ratio of the cross-section area of the narrow portion 2 at the place where it adjoins the large portion 3 does not exceed 0.5.

Abstract: An optical fiber hydrophone system in which a single optical fiber is used for all of the acoustical sensors in the system. A signal source and detector provides an optical signal in selected form, such as continuous or pulsed and detects and extracts an identifiable output signal. Each sensor is in the form of a sensing portion of the single optical fiber. Each sensing portion includes two optical reflectors separated one from another by a predetermined length of said optical fiber. Variations in acoustical pressure incident on the sensing portion causes a change in the predetermined length. This causes reflected portions of the optical signal to interfere with one another. Such interference is detectable for extraction of the identifiable output signal. In one form each sensing portion has two terminal branches of a mechanically deformable material, deformable in response to the fluctuations in acoustical pressure.

Abstract: A method of measuring the temperature in a high pressure furnace of a hot isostatic pressing apparatus, wherein a closed-end pipe having its inside communicated with the inside of the high pressure furnace and enabling a pressure medium to pass therethrough is disposed in the furnace, an incident top end of an optical fiber, a bundle of optical fibers or like other equivalent optical rod-like memeber is disposed to the open end of the closed-end pipe so as to be capable of receiving thermally radiated light from the inside of the closed-ended pipe and an exit rear end thereof is led out through a cover and to the outside of said high pressure vessel and a measuring system is connected to said exit rear end to detect heat radiation power from the top end of the closed-end pipe to thereby measure the temperature inside of the furnace.