Abstract: An electric field sensor includes an electric field sensor head (13) for varying an intensity of a propagating light beam from a light source (19) in response to an electric field intensity of an input signal received by a reception antenna (11). A photo-electric converter (21) converts the propagating light beam into an output signal. A correcting device (27) compares the output signal with a reference signal to produce and supply a control signal to the photo-electric converter.

Abstract: A technique and circuit for measuring direct current flowing through a conductor at a high voltage employs a capacitor connected in series with the conductor, and a neon lamp connected in parallel with the capacitor. The series connected capacitor and conductor are connected to a high voltage source such that the current flowing through the series connected capacitor and conductor charges up the capacitor. Since the capacitor and the neon lamp are connected in parallel, the voltage across the electrodes of the neon lamp follows the voltage across the capacitor. When the voltage across the electrodes of the neon lamp reaches the lamp's ignition voltage, the neon lamp fires, and discharges the capacitor until the voltage across the electrodes of the neon lamp falls to the lamp's extinction voltage. The light signal generated by the neon lamp is picked up by a fiber optic cable and transmitted to a remote receiver for processing.

Abstract: In this system, reflected light from an electro-optic probe is detected by a photodetector, and only a voltage signal of a frequency which is an integral multiple of the fundamental frequency of the output voltage from the photodetector is detected. The frequency characteristics of the output voltage from the photodetector can be measured at a high speed and a high accuracy.

Abstract: An apparatus and method for measuring the current distribution in an integrated circuit with high time resolution is described incorporating a magneto-optic film, a linearly polarized light beam and a means for measuring the magneto-optic polarization rotation of a light beam and circuitry for synchronizing test pulses in an integrated circuit. The invention overcomes the problem of determining current distribution as a function of time and location in an integrated circuit with 1 psec time resolution and 1 micrometer spatial resolution.

Abstract: An apparatus and method for optical heterodyne conversion and a radiation source and integrated diagnostics using the apparatus and method are disclosed. The radiation source can operate in a high-power narrow-band mode in which a constant-frequency output is provided or in a low-power broadband mode in which the frequency is tunable to allow the radiation source to act as a sweep oscillator. The apparatus or photomixer includes two sets of interdigitated conductive electrodes formed on top of a crystal lattice formed of column III-V compounds, particularly InAlGaAs compounds. Additional column V atoms are interspersed within the lattice structure to form defect energy states in the bandgap of the host material. The region of the material between the interdigitated electrodes is illuminated by optical radiation containing two different frequencies. Photon absorption in the material causes a current at the difference frequency to be generated and coupled to the interdigitated electrodes.

Abstract: A variable color display system exhibits a display unit in a color in accordance with the value of a limit. The color signals are developed in accordance with the value of the limit and applied to a color control input of the display system to control its color substantially continuously.

Abstract: An alternating current in a conductor is measured using a Faraday element. The Faraday element is disposed around the conductor and linearly polarized light is supplied to the device. The plane of polarization of the linearly polarized light is rotated through a measuring angle in the Faraday element. This light is divided into two light signals having planes of polarization at right angles to each other. The two light signals are converted into corresponding electrical signals by optoelectric converters. These electric signals are split into their direct signal components and their alternating signal components. The quotients of the difference and sum of the alternating signal components as well as the quotient of the difference and sum of the direct signal components are calculated. A temperature-compensated measuring signal is derived from these calculated quotients.

Abstract: An electrooptic probe for measuring voltage of an object without contact with the object. The electrooptic probe according to the present invention includes an electro-optic material having a refractive index to light that varies in accordance with an electric field, a conductive reflecting film for reflecting an incident beam transmitted through the electro-optic material, fixed to an end face of the electro-optic material facing the object to be measured, a transparent electrode fixed on the other end face of the electro-optic material, and a high permittivity film fixed on an end face of the reflecting film facing the object to be measured.

Abstract: An optical voltage/electric field sensor includes a crystal having a refractive index distribution which depends on an electric field applied thereto, wires for leading the electric field onto the surface of the crystal, a detector to detect changes in the refractive index distribution, and a transparent material having a low extinction coefficient and dielectric constant surrounding the crystal. Such a sensor is particularly useful for measuring the voltage of high frequency dryers.

Abstract: A magneto-optical element is of a rare-earth iron garnet crystal expressed at least by formula 1, and a element in whose composition range the value of X is set at 0.8.ltoreq.X.ltoreq.1.3; that of Y at 0.2.ltoreq.Y.ltoreq.0.4; that of Z at 0.1.ltoreq.Z.ltoreq.0.9; and that of W at 0.ltoreq.W.ltoreq.0.3; and R element is made at least one or more kinds of rare-earth elements. An optical magnetic field sensor is composed in such a manner that light diffracted by magnetic domain structure of rare-earth iron garnet crystal can be detected up to a higher-order light by optical fiber on light output side through optical system arrangement. A magnetic field measuring equipment composed of the optical magnetic field sensor has a linearity error of .+-.1.0% or less within a magnetic field range 5.0 Oe to 200 Oe, and allows a measuring accuracy higher than with prior art equipment.(Bi.sub.X Gd.sub.Y R.sub.Z Y.sub.3-X-Y-Z)(Fe.sub.5-W Ga.sub.W)O.sub.

Abstract: In an optical unit (a), a first polarizer, a first light wave phase modulator (a Pockels device), a second light wave phase modulator, and a second polarizer are arranged in this sequence. A voltage to be measured is applied to the first light wave phase modulator. A control modulation voltage which has a frequency higher than that of the voltage to be measured is applied to the second light wave phase modulator. A signal processing unit (b) consists of: an O/E converter which converts the intensity of light output from the optical unit (a) into an electric signal; a phase shifter which shifts the phase of the control modulation voltage applied to the second light wave phase modulator by .pi./2 radians; an adder 16 which adds an output of the O/E converter 17 to that of the phase shifter 15; and a demodulator c which demodulates output of the adder 16.

Abstract: An apparatus of this invention emits light onto an EO probe and detects the light reflected by the EO probe by using an MSM photodetector. The MSM photodetector is applied with a voltage of a frequency nf.sub.0 +.DELTA.f.

Abstract: An apparatus and method for determining the power demand from a conventional watt-hour meter including a disk having a black mark imprinted on an edge thereof wherein the disk rotates in proportion to the amount of electrical power demanded by the energized electrical equipment connected thereto. The method comprising the steps of: positioning a scanning laser beam in front of the rotating disk of the watt-hour meter in a position transverse to the rotating disk such that the edge of the rotating disk is within the field of view of the scanning laser beam, scanning and then detecting the passings of the black mark as the disk rotates through at least two revolutions and computing the power demanded by the connected and energized electrical equipment based upon the amount of time between successive passings of the black mark.

Abstract: A self-contained personal microwave and RF detector, which includes, inter alia, the housing and associated electronics of a standard hearing aid, is configured to produce an audible indication to a wearer thereof in response to electromagnetic fields of dangerously high levels within predetermined frequency ranges.

Abstract: An electric field sensor comprises a substrate 4, an incident optical waveguide 5 formed on the substrate 4, two branched optical waveguides 6 formed on the substrate 4 to be branched from the incident optical waveguide 5 and having refractive indexes which are variable in response to an electric field intensity applied thereto, an outgoing optical waveguide 7 formed on the substrate 4 to join the branched optical waveguides 6, and an electric field shielding member 8 formed in the vicinity of a part of the branched optical waveguides 6 for shielding an electric field. The substrate 4 may be provided with a reflection mirror 16 for reflecting light beams from the branched optical waveguides 6. The substrate 4 is made of a ferroelectric material and has polarization directions reverse to each other at portions where the two branched optical waveguides 6 are formed.

Abstract: A processing unit notifies a drive unit of a designated number N (=1, 2, . . . ). The drive unit supplies a drive signal of a frequency f.sub.0 to a target measurement device, and supplies a modulation signal of a frequency N.multidot.f.sub.0 +.DELTA.f to an optical modulator. In this state, a continuous emission light beam is emitted from a light source, incident on an E-O probe sequentially through a polarizer and a first optical system, influenced by a periodical voltage waveform generated at a target measurement portion at a fundamental period 1/f.sub.0 to modulate the polarized state, and output from the E-O probe. The optical signal whose polarized state is modulated is input to the optical modulator and modulated. Thereafter, a polarization direction is selected by an optical selection unit, and the optical signal is input to an photodetector 510 and heterodyne-detected.

Abstract: A device for measuring the voltage of a voltage source includes a number of temperature responsive displays and a circuit including a number of heating circuits, each heating circuit for heating one of the temperature responsive displays when a threshold voltage of the heating circuit is exceeded, and a printed resistor, each heating circuit being connected to a length of the printed resistor such that the voltage of the voltage source at which each heating circuit heats a temperature responsive display is a function of the ratio of the lengths of the printed resistor to which the heating circuits are connected.

Abstract: A photonic electro-optic field sensor is positioned adjacent a metallic antenna. Polarized light is passed through the field sensor, and the degree of rotation thereof is proportional to the strength of the RF signal sensed by the antenna. The resulting modulated light signal is transmitted via an optical fiber cable to a remote signal processor and is photodetected before further processing by the shielded processor electronics.

Abstract: An improved fiber optic sensor system and integrated sensor bearing assembly for detecting movement or position of a rotating wheel bearing having a multi-pole tone ring which produces an alternating magnetic field indicative of movement and position of the rotating member. A magneto-optical material, such as a bismuth garnet iron (B.I.G.) crystal, having discrete magnetic domains is positioned in the vicinity of the tone ring so that the domains align themselves to the magnetic field generated by the tone ring. A single fiber optic cable, preferably single mode fiber, carries light generated by a source of light to the B.I.G. crystal. The light passes through the B.I.G. crystal and is refracted at domain boundaries in the crystal. The intensity of the refracted light is indicative of the amount of alignment of the domains and therefore the strength of the magnetic field.

Abstract: A voltage monitor which uses the shift in absorption edge of crystalline material to measure strain resulting from electric field-induced deformation of piezoelectric or electrostrictive material, providing a simple and accurate means for measuring voltage applied either by direct contact with the crystalline material or by subjecting the material to an electric field.

Abstract: A method and apparatus for obtaining a voltage-isolated measurement channel in a measurement instrument is provided. An input signal is multiplied with a clock signal to obtain a modulated input signal that is coupled to an input winding of a balanced transformer. The modulated input signal is electromagnetically coupled from the input winding to an output winding. At the same time, the input winding and the output winding are voltage-isolated, meaning that the portion of the measurement channel coupled to the input winding is "floated" with the input signal whereas the remaining portion of the measurement channel is referenced to instrument ground. A sampling circuit coupled to the output winding samples the modulated input signal in the manner of a synchronous detector to extract the original input signal voltage which is provided to an analog to digital converter which generates the digital measurement values.

Abstract: An electric field measuring apparatus for causing an optical probe head having an electro-optic member with an electro-optic material to oppose a sample such as a semiconductor integrated circuit device and for optically measuring a voltage of an opposite portion of the sample. The electro-optic material consists of an LiTaO.sub.3 electro-optic crystal or the like, the polarization characteristics of which change depending on the electric-field strength of the sample. The electro-optic member is supported on a guide mechanism to be reciprocally movable within a predetermined stroke range in a direction of the sample. The guide mechanism is reciprocated in the direction of the sample to control the distance between the electro-optic material and the sample.

Abstract: An E-O probe for a two-dimentional voltage detecting apparatus using a fiber optic plate is provided. The fiber optic plate has a bottom face facing a measured object and a bundle of a plurality of cores separated from one another by cladding electro-optic material is attached to an end of each core at said bottom face side. A reflecting surface is provided on the bottom face side of the fiber optic plate for reflecting light back toward the side of the fiber optic plate opposite said bottom face. The refractive index of said electro-optic material varies in response to the intensity of an electric field applied to the electro-optic material. A two-dimentional voltage detecting apparatus using the E-O probe is further provided which has a high spatial resolution.

Abstract: To increase the measuring sensitivity of a simple-to-manufacture, multi-faced solid optical current sensor, at least one of the light-reflecting lateral faces is displaced radially inward with respect to the remaining light-reflecting lateral faces and has a lesser minimum distance from a center of the solid optical current sensor than the other lateral faces. Because of this displacement, the incident light beam does not move through a closed polygonal progression in the course of a single circuit around a recess for a current conductor, whose current intensity is to be measured by means of the Faraday effect. Helically overlapping displacements of the light circuit paths are created, which cause an increase in light sensitivity. The lateral face or another lateral face can also be displaced outwardly instead of inwardly.

Abstract: This invention has as its object to provide a voltage measurement apparatus which has a compact probe unit, and which can perform a measurement in a non-contact manner. The voltage measurement apparatus includes detection means for detecting an electric field generated in a space by a voltage applied to the surface of a device to be measured, light-emitting means for modulating output light by superposing a detected signal obtained from the detection means on a bias current which is supplied to inductively radiate the output light, a constant current source for supplying the bias current to the light-emitting means, extraction means for extracting a signal component of the output light from the light-emitting means, and light-transmission means for guiding the output light from the light-emitting means to the extraction means, and measures the applied voltage to the surface of the device to be measured by bringing the detection means close to the device to be measured in a non-contact manner.

Abstract: A new method is described that allows determination of the degree of molecular dissociation based on continuous, radio frequency (rf) and microwave driven discharges based on electrostatic probe and emission spectroscopy measurements only. Using this method costly laser-induced fluorescence spectroscopy (LIF) can be avoided. The method described is particularly applicable to hydrogen plasmas characterized by non-thermal electron energy distribution functions which are of great practical importance. A compact combined fiber optic/electrostatic probe facilitating the required measurements is described.

Abstract: Apparatus for providing a direct indication of the failure of an electronic ircuit including a built-in self test circuit which performs an initial test on the electronic circuit and having a visual indicator coupled thereto which becomes activated when the self test circuit senses a failure of the electronic circuit upon power being supplied thereto or during operation. The electronic circuit with the built-in test feature consists of an integrated circuit chip or a multi-chip module encapsulated in a package with the indicator means visible therethrough. The indicator consists either of a light emitting diode or fusible material which changes its appearance and becomes visible through the package upon being activated by the built-in self test circuit.

Abstract: Reflectance measurement with two monochromatic light beams having different wavelengths is used to obtain curves respective representing the relationship between an insulation film thickness of a semiconductor wafer and the gap between a test electrode and a semiconductor wafer surface. The C-V curve measurement at a fixed gap determines a total capacity of the gap and the insulation film, and a straight line representing the relationship between the gap and the insulation film thickness is obtained from the total capacity. An intersection where the two curves and the straight line cross gives the true values of the gap and the insulation film thickness.

Abstract: A fiber optic Faraday flux transformer sensor is disclosed which comprises: a closed loop of wire being responsive to a first time-varying magnetic field from a remote source for producing a secondary time-varying magnetic field which varies as a function of the first time-varying magnetic field, and an optical fiber loop having a plurality of turns arranged in a preselected configuration adjacent to the closed loop of wire and adapted to receive and pass therethrough input light having a fixed state of linear polarization. The optical fiber loop is responsive to the secondary time-varying magnetic field and to the input light for producing light having a polarization state which changes as a function of the secondary time-varying magnetic field applied thereto. In a system implentation, an optical source transmits light having a linear state of polarization to a first polarizer, which selects and sends a fixed predetermined state of polarization to the fiber optic Faraday flux transformer sensor.

Abstract: A display system comprises a display area for exhibiting in a selective color a digital value, comparator for developing a signal in accordance with a relation of the digital value to a limit, and color control for illuminating the exhibited digital value in a color in accordance with the signal.

Abstract: A process for measuring electric voltages and/or electric fields by the use of a crystal with an electro-optical (Pockels) effect. To this end, in a direction transverse to the direction of propagation (y direction) of a light wave polarized in the z direction, an electric field intensity gradient is generated in the crystal in the direction from which results a corresponding gradient in the refractive index n of the crystal. This produces a deflection of the light wave in the crystal which depends upon the field intensity and on emergence, it is used as a measure for the voltage of field intensity. A suitable sensor for this purpose is also described.

Abstract: The present invention provides a novel sensor preferably used for non-destructive measurement of the electrical characteristics of semiconductors. The sensor is easily manufactured and has a sufficiently high dielectric breakdown strength. The sensor includes an electrode mount 64 having a an electrode pattern 200 formed on a bottom surface 66a of a cone glass 66. The bottom surface 66a has a reflecting plane 66c for reflecting a laser beam, a test electrode 201, and three parallelism adjustor electrodes 111 through 113 formed around the reflecting plane 66c. The bottom surface 66a also has a guard ring 120 disposed between the test electrode 201 and the parallelism adjustor electrodes 111 through 113. An insulating film 68 covers a lower surface of the cone glass 66. Wiring formed on a inclined face 66b of the cone glass 66 is connected to external lead wires at the upper end of the wiring.

Abstract: A fiber optic, Faraday-effect sensing coil has very low linear and circular birefringence, which remains stable over a wide range of temperatures. The coil is fabricated from a spun fiber having an effective linear beat length of 100 meters or more, and is annealed after being formed into the coil. The coil has improved discrimination for magnetic fields associated with electric current-carrying cables, and may be incorporated into an optical current transducer (OCT), either interferometric or polarimetric.

Abstract: A high-resistance compound semiconductor 12 is epitaxially grown on a low-resistance compound semiconductor 11 and a dielectric reflecting film 13 is formed thereon, thereby forming a monolithic sensor 10. As the low-resistance compound semiconductor 11, a compound semiconductor is used which has a large bandgap so as to enable probe light to pass therethrough without being absorbed and which has a lattice constant and a thermal expansion coefficient, which are close to those of the high-resistance compound semiconductor. In addition, since the low-resistance compound semiconductor 11 also serves as an electrode, a compound semiconductor which has a resistivity of 10.sup.+1 .OMEGA.cm or less is used. Since the shorter the wavelength of the probe light used, the larger the retardation change and the larger the signal output, a compound semiconductor which has a large bandgap is used as the high-resistance compound semiconductor 12 so that light of short wavelength can be used.

Abstract: An optical sensor comprising: a light irradiation means for irradiating a linearly polarized light having a wavelength of 740 to 890 nm; a magneto-optical element having a composition of Y.sub.3-X Tb.sub.X Fe.sub.5 O.sub.12 (0.3.ltoreq..times..ltoreq.0.8) for Faraday rotating the linearly polarized light to output a rotated polarized light; and a detecting means for modulating in intensity the rotated polarized light which has been Faraday rotated by the magneto-optical element and detecting a light output of the rotated polarized light from the magneto-optical element. This magneto-optical sensor has a high sensibility and an excellent temperature characteristics under condition of low-magnetic field. When the optical sensor 10 is additionally provided with an electro-optical element having Pockels effect in parallel to the magneto-optical element, it becomes possible to measure not only current intensity but also voltage intensity.

Abstract: An electro-optic material constituting an E-O probe has a refractive index for light from a semiconductor laser, which is changed in accordance with an electric field from a device to be measured. The electro-optic effect is substantially canceled upon incidence of light from an Ar.sup.+ laser. A mechanical chopper modulates the light emitted from the Ar.sup.+ laser and causes the light to be incident on the E-O probe. A lock-in amplifier detects the polarized state of the light reflected by the E-O probe synchronized with the modulation, thereby measuring the voltage of the device.

Abstract: A method and an apparatus for electro-optic sampling measurement of electrical signals in integrated circuits, capable of improving the reproducibility of the measurements and calibrating the voltage accurately. The changes of beam intensity of a laser beam reflected from an electro-optic probe is measured by using a low frequency signal of a known voltage level to determine a relationship between the changes of beam intensity and gaps between the electro-optic probe and the integrated circuit, then a proportionality of the change of beam intensity and an absolute voltage level for a desired gap is determined according to the determined relationship. Then, the change of beam of intensity at a desired measurement position with a desired gap is measured by using a high frequency signal and the absolute voltage level of the high frequency signal is determined according to the measured change of beam intensity and the determined proportionality.

Abstract: An optical sensor comprising: a light irradiation means for irradiating a linearly polarized light having a wavelength of 740 to 890 nm; a magneto-optical element having a composition of Y.sub.3-x Tb.sub.x Fe.sub.5 O.sub.12 (0.3.ltoreq.x.ltoreq.0.8) for Faraday rotating the linearly polarized light to output a rotated polarized light; and a detecting means for modulating in intensity the rotated polarized light which has been Faraday rotated by the magneto-optical element and detecting a light output of the rotated polarized light from the magneto-optical element. This magneto-optical sensor has a high sensibility and an excellent temperature characteristics under condition of low-magnetic field. When the optical sensor 10 is additionally provided with an electro-optical element having Pockels effect in parallel to the magneto-optical element, it becomes possible to measure not only current intensity but also voltage intensity.

Abstract: An electric current is measured by a device that includes a magneto-optical element which acts as a Faraday rotator wherein a plane of polarization of polarized light passing therethrough is rotated as a function of a magnetic field surrounding that element. A light emitter and polarizer send a polarized light beam through the magneto-optical element. First and second light detectors are located within the single beam of light emerging from the magneto-optical element. Associated with the two detectors are separate polarizers respectively oriented at -45 degrees and +45 degrees to a polarization plane of the light beam emerging from the magneto-optical element when no electric current flows through the conductor. The magnitude of the current in the conductor is determined by comparing signals from the two light detectors.

Abstract: The sensor head (1) is intended for a fiberoptic current measuring device. It exhibits a twisted low-birefringence LB fiber (14) which is guided around a current conductor (2) and serves to conduct polarized light. Using the LB fiber (14), the Faraday rotation of the polarized light, which rotation is generated by the magnetic field (H) of the current (J) to be measured, is detected. The LB fiber (14) is spliced at its two ends in each instance with one of two polarization-conserving, light-conducting HB fibers (6, 7), one (6) of which supplies the polarized light. The two HB fibers (6, 7) are secured in each instance in the vicinity of the two splice locations (19, 20) with the absorption of the torsional force generated by the twisting of the LB fiber (14).In spite of having a simple and sturdy structure, the sensor head (1) is distinguished by a high degree of measurement accuracy.

Abstract: An E-O probe with improved spatial resolution has a light transmissive base part, an electro-optic material which is fixed to the base part and has an index of refraction which varies in response to an electrical field from a measured object, and a mirror which is fixed to the electro-optic material and reflects an incident beam penetrating the base part and the electro-optic material. The mirror is formed to be smaller than the incident beam in diameter. The electro-optic material is formed very thin.

Abstract: An electro-mechanical induction watt-hour meter has a rotatable disc and a projection on the base directed into the meter terminating in proximity of the rotatable disc. The projection is part of a pulse initiator system where a pulse signal is transmitted through a selected area of the base that is transparent to the signal. A signal is generated externally of the meter and chopped by rotation of the disc providing a pulse signal that passes through the base of the meter to a receptor external to the meter. The signal generator and the pulse signal receptor are both located in the enclosure defined by the base of the meter and the receptacle socket for the meter. The generated signal is disclosed as a light beam that, by way of light guides on the meter base, is directed to one side of the rotating disc and is directed by one light guide and to the other side of the disc where another light guide returns the chopped or pulsed signal to the receptor.

Abstract: In phase difference detecting method, circuit, and apparatus of the present invention, a voltage signal having a predetermined frequency is applied to a photoconductive light-receiving device, and an optical signal is received by this photoconductive light-receiving device. A current generated upon reception of light and flowing in the photoconductive light-receiving device reflects a product value of the voltage signal and the optical signal, and contains a DC component according to a phase difference between the voltage signal and the component of the optical signal having the same intensity modulation frequency as that of the voltage signal.

Abstract: An optical current transformer for measuring a current flowing through a conductor by transmitting a light beam about the current-carrying conductor includes four Faraday effect glass rods. For transmitting the light beam, the rods are arranged in a rectangle forming a through hole for the conductor. Three optical path changing pieces are included, each for redirecting the light beam from one of the glass rods to a different one of the glass rods, and each being positioned at a different corner of the glass rod rectangle. Two substrate plates, each having a through hole for the conductor, are positioned at opposite sides of the glass rod rectangle to sandwich the glass rods and the optical path changing pieces therebetween. The glass rods are substantially fixed while allowing for thermal expansion and contraction of the glass rods.

Abstract: An electrical current measuring device, for measuring the current in an electrical conductor (11), includes first and second measurement channels. Each of these channels includes a sensor (12) adapted to be located adjacent the conductor (11) and coupled via optical fibers (14,16) to source circuitry (18) and detector circuitry (20). The sensor (12) incorporates a material (22) which exhibits the Faraday magneto-optic effect and the source circuitry (18) is arranged to deliver an unpolarized light signal which is subsequently polarized by a first polarizer (23) to enable a linearly polarized light signal to be incident to the material (22). The quantum of rotation in the plane of polarization imposed on the signal emerging from the material (22) is monitored via a second polarizer (24) by the detector circuitry (20) as a measure of the electrical current flowing in the conductor (11).

Abstract: A DC current sensor with an exciting core of soft magnetic material and formed with a pair of tubular bodies, each tubular body being positioned in parallel with the other to provide therebetween a space, through which passes a wire conducting a current to be detected; a detecting core formed with the side faces of a pair of tubular bodies and two plate-like members of soft magnetic material, each of which connecting integrally with each of the inside edges thereof near an opening of the tubular bodies to form a rectangular frame-shaped member as a whole; exciting coils, each of which magnetically energizing the exciting core in the direction perpendicular to the plane of the detecting core; detecting coils, each of which being wound around the detecting core; and applying an alternating current to the exciting coils to periodically and magnetically saturate the rectangular-shaped portions of the detecting core and exciting core, energizing the exciting coils to modulate a magnetic flux produced in the detect

Abstract: A magneto-optical element is of a rare-earth iron garnet crystal expressed at least by formula 1, and a element in whose composition range the value of X is set at 0.8.ltoreq.X.ltoreq.1.3; that of Y at 0.2.ltoreq.Y.ltoreq.0.4; that of Z at 0.1.ltoreq.Z.ltoreq.0.9; and that of W at 0.ltoreq.W.ltoreq.0.3; and R element is made at least one or more kinds of rare-earth elements. An optical magnetic field sensor is composed in such a manner that light diffracted by magnetic domain structure of rare-earth iron garnet crystal can be detected up to a higher-order light by optical fiber on light output side through optical system arrangement. A magnetic field measuring equipment composed of the optical magnetic field sensor has a linearity error of .+-.1.0% or less within a magnetic field range 5.0 Oe to 200 Oe, and allows a measuring accuracy higher than with prior art equipment.(Bi.sub.x Gd.sub.y R.sub.z Y.sub.3-x-y-z)(Fe.sub.5-w Ga.sub.w)O.sub.

Abstract: A general-purpose magnetic field sensor capable of sensitively measuring uniform magnetic fields includes a magneto-optic (Faraday-effect) sensor and a flux concentrator. Both the magneto-optic sensor and the flux concentrator have high magnetic permeability. The magneto-optic sensor is positioned in close proximity to the flux concentrator. The combination of the high-permeability magneto-optic material and the flux concentrator creates a magnetic circuit which efficiently concentrates the magnetic field into the magneto-optic sensor, and greatly enhances the measurement sensitivity. The preferred embodiment uses a pair of cylindrical flux concentrators in axial alignment. A sensing beam passes through a central axis hole in the cylindrical flux concentrators. The Faraday effect sensor is co-axially aligned with the holes in the cylindrical flux concentrators. The concentrators and Faraday effect sensor create a continuous flux concentrating magnetic circuit.

Abstract: A sensor system includes a sensor head, an optical source, and a measurement apparatus. The sensor head includes a beamsplitter having first, second, third, and fourth ports, the beamsplitter being responsive to light selectively applied to the first, second and third ports for passing light of a first input polarization state from the first port to the second port, for passing light of a second input polarization state orthogonal to the first input polarization state from the first port to the third port, and for collectively passing light of a first output polarization state and light of a second output polarization state orthogonal to the first output polarization state from the third port to the fourth port. The optical source means provides light to the first port.

Abstract: To provide an E-O probe which can measure a voltage distribution in a fine region while enlarging it. A grounded, transparent electrode 2 and an electrooptic member 3 such as LiTaO.sub.3 are successively fixed to and below a support 1. There are a plurality of conical, conductive members 5a-5e arranged below a reflection film 4 in such a manner that the bottom surfaces thereof are fixed to the lower surface of the reflection film 4 and that the lower ends thereof project downward. Spaces between the plural, linear, electric needles 5a-5e become narrower toward a measured object located below them, whereby voltages in a fine region in the measured object can be guided as enlarged to the electrooptic member 3.