Abstract: The present invention relates to an electro-optic sampling oscilloscope in which an electric field generated by a signal to be measured is coupled with an electro-optic crystal, and an optical pulse outputted from an optical pulse output circuit is caused to enter the electro-optic crystal, and the waveform of the signal to be measured is observed using the polarization state of the optical pulse. The optical pulse output circuit has as the input light thereof a sample optical pulse amplified by an optical amplifier circuit, and outputs, as an optical pulse, the output from an optical filter which blocks the propagation of the spontaneously emitted light of the optical amplifier circuit.

Abstract: A voltage sensor for measuring the voltage on high voltage lines is formed by an electrically isolating section of dielectric material that structures the electric field generated by a voltage difference between the two ends of the isolating section and provides screening of the electric field from other electric field sources external to the isolating section. At least one electric field sensor is provided to sense the electric field in the isolating section the output(s) of which are weighted and combined to provide an accurate measurement of the voltage between the two ends. The electric field sensors are located and their outputs are combined so that error in the voltage measurement due to the influence of external electric field sources is within an acceptable range.

Abstract: A laser beam is used to probe an integrated circuit device under test. A single laser provides a single laser pulse which is divided into two pulses, both of which are incident upon the device under test. After the two pulses interact with the device under test, the two pulses are separated and detected by two photo detectors. The electrical signals output by the photo detectors are then subtracted, which cancels out any common mode noise induced on both pulses including noise due to mechanical vibration of the device under test and also any noise from the laser. The difference signal can be used to reproduce a time varying signal in the device under test.

Abstract: A reusable miniaturized detector that utilizes magneto-optic elements to detect the occurrence of an electrostatic discharge during the manufacture or handling of electrostatic discharge sensitive electronic components and circuit boards. The device may also be used to determine the polarity and magnitude of the electrostatic discharge. The device may be manually or automatically read, either by removing the device from the environment being monitored or continuously monitoring in situ. The device can also be configured to provide protection to some electrostatic discharge events which could damage sensitive components being monitored.

Abstract: An analog to digital converter has an optical pulse source generating an optical pulse chain having a plurality of optical pulses. An optoelectronic digitizer has a first input receiving the optical pulse chain. The digitizer has a second input for receiving the analog signal to be converted. The digitizer has a plurality of digital outputs. Each of the digital outputs corresponds to a range value. An electronic encoder receives the plurality of digital outputs. The encoder has an output in a predetermined digital format.

Abstract: A reusable miniaturized detector that utilizes magneto-optic elements to detect the occurrence of an electrostatic discharge during the manufacture or handling of electrostatic discharge sensitive electronic components and circuit boards. The device may also be used to determine the polarity and magnitude of the electrostatic discharge. The device may be manually or automatically read, either by removing the device from the environment being monitored or continuously monitoring in situ. The device can also be configured to provide protection to some electrostatic discharge events which could damage sensitive components being monitored.

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≦X≦1.3; that of Y at 0.2≦Y≦0.4; that of Z at 0.1≦Z≦0.9; and that of W at 0≦W≦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. (BiXGdYRZY3-X-Y-Z) (Fe5-WGaW) O12  (formula 1).

Abstract: An electro-optic sampling oscilloscope (or EOS oscilloscope) is designed to perform measurement such that an electro-optic sampling probe (i.e., EOS probe) is brought into contact with a measured circuit. Optical pulses are input to the EOS probe, wherein they are varied in polarization states in response to the measured circuit. Then, an electric signal output from the EOS probe is amplified to produce a receiving light signal. The receiving light signal is subjected to sampling operations using a first pulse signal to produce detection data, while it is also subjected to sampling operations using a second pulse signal to produce noise data. Herein, the first pulse signal consists of pulses which emerge in synchronization with the optical pulses respectively, while the second pulse signal delays from the first pulse signal by a prescribed delay time. Then, measurement data are produced by subtracting the noise data from the detection data.

Abstract: This invention is a method for the non-invasive and safe testing of telecommunication and broadcast towers or other airwave or cable transmitting and receiving devices and related equipment using a calibrated infrared camera and computer, computer software, a color monitor or a color printer. This novel method of testing and determination of potential problem sites and failure prediction can be conducted from ground level and at some distance from the tower or device being tested, substantially reducing the risk of falling from extreme heights or being exposed to hazardous EMF fields, microwave or RF transmission waves, all of which are fatal or hazardous to health of the person conducting the testing.

Abstract: Polarized measuring light propagates through a sensor device and is then split into two differently linearly polarized partial light signals. An intensity-normalized measuring signal is derived from the two partial light signals and their direct components.

Abstract: A reusable miniaturized detector that utilizes magneto-optic elements to detect the occurrence of an electrostatic discharge during the manufacture or handling of electrostatic discharge sensitive electronic components and circuit boards. The device may also be used to determine the polarity and magnitude of the electrostatic discharge. The device may be manually or automatically read, either by removing the device from the environment being monitored or continuously monitoring in situ. The device can also be configured to provide protection to some electrostatic discharge events which could damage sensitive components being monitored.

Abstract: Amplitude modulated optical beam induced current (AMOBIC) created by irradiating an internal PN junction of an integrated circuit (IC) (20) is used to determine a voltage level of the internal PN junction. In one embodiment, an IC (20) requiring high current and operating above the kilo-Hertz frequency range is monitored using a pulsed infrared laser beam (42). An AMOBIC signal is created when an internal PN junction is irradiated with the pulsed infrared laser beam (42). By using a pulsed infrared laser beam (42) an OBIC signal is amplitude modulated (AM) to a carrier frequency. This carrier frequency is selected so that the AMOBIC signal is large when compared to the various noise sources present at or near the carrier frequency. The noise rejection resulting from frequency shifting of the OBIC perturbation is further increased by selectively attenuating transient current spikes occurring at IC clock edges, whereby IC testing is further improved.

Abstract: An optical magnetic field sensor probe for detecting a magnetic field to be measured as an output light intensity, by disposing a polarizer, a magneto-optical device, and an analyzer mutually different in the transmission and polarization direction with respect to said polarizer, along the running direction of light, has an input optical fiber for feeding into to said polarizer through a first lens, and an output optical fiber for emitting an output light from said analyzer through a second lens, wherein said input optical fiber, said first lens, said magneto-optical device, said second lens and said output optical fiber are composed in a confocal optical system, and said first lens and said second lens are drum lenses.

Abstract: A photoconductive method or apparatus for measuring high frequency signals using a relatively inexpensive photoconductive material with a relatively long duration or recombination time. The photoconductive method or apparatus utilizes a photoconductive element of photoconductive material such that the duration or recombination time of the photoconductive material is longer than the pulse width of the signal to be measured. As such, the photoconductive element produces a step function response to the signal to be measured rather than a rectangular response with respect to the signal to be measured. The photoconductive element avoids the need to sacrifice measurement sensitivity by introducing defects in the photoconductive material to shorten the recombination time or duration. The measurement bandwidth of the photoconductive element is not limited by the recombination time of the photoconductive material which is mostly dominated by the carrier lifetime.

Abstract: In mutually opposite directions, two light signals traverse an optical series circuit including a first multi-mode fiber, a first polarizer, a Faraday sensor device, a second polarizer and a second multi-mode fiber. An intensity-normalized measuring signal is derived with the aid of direct signal components from light intensities of the two light signals after traversal of the series circuit.

Abstract: A magnetic measuring apparatus measures, at a high spatial resolution, a magnetic field generated by a current flowing in one of a plurality of highly packed parallel wires on a printed-circuit board. The magnetic measuring apparatus includes a magnetic field detector for detecting a magnetic field generated by a current flowing in one of a plurality of parallel wires, a measuring unit for measuring a magnetic field intensity based on an output signal from the magnetic field detector, an input unit for entering a pitch of the parallel wires and a spatial resolution characteristic of the magnetic field detector, a processor for calculating a height of the magnetic field detector from the one of the parallel wires based on the pitch of the parallel wires and the spatial resolution characteristic, and a scanning device for scanning the magnetic field detector into a position determined by the processor.

Abstract: The subject matter of the present invention is a fiber-optic outdoor high-voltage sensor 1. The known sensor principle is based on the fact that a piezoelectric quartz cylinder 3 wound with a glass fiber 4a effects a voltage-proportional fiber strain which is measured interferometrically. According to the invention, a 420 kV outdoor sensor 1 is created by virtue of the fact that several quartz cylinders 3 and electrically conductive spacing elements 5 are arranged in an alternating fashion one behind another and are sealed in a silicone-shielded 17 insulating tube 16 by means of polyurethane 18 or silicone 21. Dividing the high voltage between several spaced, E-field integrating sensor elements 2 permits simple field control and a very high measuring accuracy. In addition, the fiber-optic voltage sensor 1 is distinguished by a low outlay on insulation, compactness and low weight, and can easily be scaled to other voltage levels and be effectively combined with optical current sensors 38.

Abstract: A glass sorting machine optically sorts glass cullet according to different color characteristics by irradiating the cutlet with red, green and blue light as the cullet are passed through a sensing region between a light source and light sensors responsive to the different light colors. The attenuation levels of the different light colors are measured by the sensors as the cullet passes through the sensing region. The machine analyzes the attenuation levels to determine the color characteristics of the cullet. A collimator is typically used to enhance shadow definition. In one embodiment, a pixel grid map is made of the sensing region and each cullet that passes through the sensing region. Mapped on to each grid is a red, green, and blue digital signal. Attenuated signals are compared against baseline values to determine the attenuation for given cullet. The pixel grid map may be used with a data erosion technique to compensate for refraction.

Abstract: A glass fiber sensor for measuring an electrical current, the glass fiber core being a heavy flint glass having its composition modified by the addition to the glass composition of a source of a selected rare earth ion, whereby the Verdet constant value of the glass is reduced without unduly increasing the value of the photoelastic coefficient.

Abstract: An electro-optic voltage sensor comprises a voltage divider connected to an electric line and to ground and having two insulative compartments separated by an intermediate electrode connected to a Pockels cell. The intermediate electrode supplies to the Pockels cell a reduced voltage derived from the voltage supplied by the electric line to the voltage divider. Each insulative compartment comprises a homogeneous dielectric block with a thickness dependent on the division ratio of the voltage divider. The electro-optic voltage sensor has a very high safety level vis a vis the risk of strong short-circuits combined with mechanical and thermal stability guaranteeing great accuracy of operation and great reliability without special maintenance requirements.

Abstract: A miniature electro-optic voltage sensor system capable of accurate operation at high voltages without use of the dedicated voltage dividing hardware. The invention achieves voltage measurement without significant error contributions from neighboring conductors or environmental perturbations. The invention employs a transmitter, a sensor, a detector, and a signal processor. The transmitter produces a beam of electromagnetic radiation which is routed into the sensor. Within the sensor the beam undergoes the Pockels electro-optic effect. The electro-optic effect produces a modulation of the beam's polarization, which is in turn converted to a pair of independent conversely-amplitude-modulated signals, from which the voltage of the E-field is determined by the signal processor. The use of converse AM signals enables the signal processor to better distinguish signal from noise.

Abstract: A voltage sensor utilizing a non-reciprocal phase shift induced by a time variation of an electric field of the voltage to be measured. A light source provides broadband light to a polarizer. The polarized light is distributed to two linear polarizations. The two polarizations of light are provided with a dynamic or static phase shift relative to each other before or after being birefrigently modulated with an electro-optic sensor in accordance with the electric field of a voltage to be measured. The modulated light goes through a delay line that is terminated with a quarter-wave plate and mirror. The quarterwave plate may be an optical fiber. The portion of light entering the quarter-wave device in a first polarization is reflected in a second polarization and the portion of light entering the quarter-wave device in the second polarization is reflected in the first polarization. The electro-optic sensor again birefringently modulates the light.

Abstract: A process for creating an electronically addressable display includes multiple printing operations, similar to a multi-color process in conventional screen printing. In some of the process steps, electrically non-active inks are printed onto areas of the receiving substrate, and in other steps, electrically active inks are printed onto different areas of the substrate. The printed display can be used in a variety of applications. This display can be used as an indicator by changing state of the display after a certain time has elapsed, or when a certain pressure, thermal, radiative, moisture, acoustic, inclination, pH, or other threshold is passed. In one embodiment, the display is incorporated into a battery indicator. A sticker display is described. The sticker is adhesive backed and may then be applied to a surface to create a functional information display unit. This invention also features a display that is both powered and controlled using radio frequencies.

Abstract: Linearly polarized measuring light is split after traversing a Faraday sensor device into two partial light signals having planes of polarization inclined at 45.degree.. A measured signal, which is proportional to the tangent of the Faraday rotation angle, is derived from the two partial light signals.

Abstract: A radiation measurement system includes a dipole antenna (4,18) for radiating an EM field in response to an electrical signal generated by an opto-electrical converter (12). The opto-electrical converter (12) is provided with an optical signal representing the EM field to be emitted. Optical signals avoid disturbance of the EM field by a coaxial cable required to feed the antenna. In order to obtain an ideal dipole antenna with well known radiation properties, an inner conductor (16) is used to couple the signal from the opto-electrical converter (12) to both halves (4,18) of a hollow dipole antenna. FIG.

Abstract: Apparatus and methods for characterizing free-space electromagnetic energy, and in particular, apparatus/method suitable for real-time two-dimensional far-infrared imaging applications are presented. The sensing technique is based on a non-linear coupling between a low-frequency electric (or magnetic) field and a laser beam in an electro-optic (or magnetic-optic) crystal. In addition to a practical counter-propagating sensing technique, a co-linear approach is described which provides longer radiated field-optical beam interaction length, thereby making imaging applications practical.

Abstract: A Faraday rotation angle varying apparatus for controlling a Faraday rotation angle of a light beam passing through a garnet single crystal having a Faraday effect by applying external magnetic fields to the garnet single crystal in two or more of directions and varying a synthetic magnetic field synthesized from the external magnetic fields is disclosed. According to an aspect of the present invention, the garnet single crystal has the (111) plane polished and the light beam is allowed to pass through the garnet single crystal along the <111> direction of the garnet single crystal perpendicular to the (111) plane. A displacement path of a synthetic vector of the external magnetic fields is within a fan-shaped range (peripheral lines of the fan-shape inclusive) of a stereographic projection chart of the garnet single crystal with the (111) plane taken as the center of the chart.

Abstract: A laser probe for measuring a magnetic field is disclosed. A polarized laser beam is passed through a magneto-optic crystal in the presence of an unknown magnetic field. The rotation of the polarization which occurs through the magneto-optic crystal is measured in order to determine the magnitude of the magnetic field. The measured magnetic field is used to determine, for example, the current through a conductor such as an interconnect line on a semiconductor chip. A method of calibrating the magnetic field using a known magnetic from a solenoid is also disclosed. Further disclosed is a method of providing a zero-reference current by momentarily stopping the chip clock.

Abstract: Radio-interrogated surface-wave technology sensor, in which the sensitive element (12) is an impedance which is electrically connected as termination to a surface-wave structure (26) of the sensor.

Abstract: An optical sensor apparatus capable of accurate measurement without using a filter circuit, and therefore being further capable of pulse driving an LED and thus reducing power consumption, is provided. To achieve such an optical sensor apparatus, when an optical current sensor 10 is not sensing the current to be measured, an optical current sensor signal processing circuit 11 first supplies dc light of a specific intensity to the optical current sensor 10, and then adjusts the intensity of the light so that the intensity of light returned from the optical current sensor 10 to the signal processing circuit 11 is a specific predetermined value. When the optical current sensor 10 is sensing the current, the signal processing circuit 11 electrically processes the optical signal from the optical current sensor 10 to measure the current.

Abstract: An electrooptic voltage waveform measuring apparatus, which includes an electrooptic element having an electrooptic effect; a first electrode mounted on the electrooptic element and electrically coupled to an object to be measured; and a first light source irradiating a light on the electrooptic element. The electrooptic voltage waveform measuring apparatus further includes a polarization analyzer for analyzing a polarization state of the light passed through the electrooptic element and detecting a voltage waveform of the object; a second electrode mounted on the electrooptic element and separated from the first electrode; and an amplifier having an input terminal coupled to the second electrode and outputting a low-frequency component of the voltage waveform of the object.

Abstract: A method for temperature calibration of an optical magnetic field measurement array and a measurement array calibrated by the method include an optical series circuit having a first optical transmission path, a first polarizer, a Faraday sensor device, a second polarizer, and a second optical transmission path. The optical series circuit is temperature-calibrated by adjusting the polarizer angles of the two polarizers in a special way. The calibration method functions even if the intrinsic axis of the linear double refraction in the sensor device is unknown.

Abstract: A modulator and an electro-optic sensor having the modulator for effectively detecting defects in an LCD panel. The electro-optic sensor includes a modulator including a body, a light reflecting member formed on a portion of the body, and a blower formed on another portion of the body; a light source for generating light to the modulator; and a processing unit for processing a light from the modulator.

Abstract: An optical magnetic field sensor probe for detecting a magnetic field to be measured as an output light intensity, by disposing a polarizer, a magneto-optical device, and an analyzer mutually different in the transmission and polarization direction with respect to said polarizer, along the running direction of light, has an input optical fiber for feeding into to said polarizer through a first lens, and an output optical fiber for emitting an output light from said analyzer through a second lens, wherein said input optical fiber, said first lens, said magneto-optical device, said second lens and said output optical fiber are composed in a confocal optical system, and said first lens and said second lens are drum lenses.

Abstract: An active optical current-measuring system (2) including a sensor (4) which is provided with current connecting busbars (12, 14) and a light guide connector. The sensor includes two parts (8, 10) which, when assembled, form a hollow cavity (16) within which an electronic sensor component (6) is mounted. The electronic sensor is connected at the output to the light guide connector. A measuring resistor is provided as the sensor (4). The current-measuring system (2) is also capable of detecting direct currents. The electronic sensor component,(6) is mechanically protected and electromagnetically shielded.

Abstract: Two light signals pass, in opposite directions, through a series circuit comprising a first optical fiber, a first polarizer, a Faraday sensor device, a second polarizer and a second optical fiber. To set the working point, additionally, the planes of polarization of both light signals are reciprocally rotated by a predetermined angle of rotation by rotation means between the two polarizers. From light intensities of the two light signals, after passing through the series circuit, a measuring signal is determined which is independent of vibrations and bending influences in the optical fibers.

Abstract: The fiber optic transducer may take the form of a current sensor, and includes a first light path which is defined by a light transmitting element (19) and a second light path which is defined by a coil (10) of optical fiber (11). The coil-forming optical fiber ( 11) has a length which is significantly greater than that of the light transmitting element (19). A modulated light source (14) is provided for directing light simultaneously into both the first and second light paths. Also, the transducer includes detector/processing circuitry (15 to 17 and 20 to 24) for detecting light exiting from the light paths during successive time periods that include first and second time intervals t.sub.1 and t.sub.2.

Abstract: The present invention provides an electro-optical isolation system for coupling an electronic measuring device to a device under test for making accurate measurements of signals within a wide frequency range while the device under test is being subject to high power electrical disturbances. The invention provides an increased rejection of high common mode signals and reduction of undesired self-capacitance by implementing a shielded handheld transmitter unit having an integrated measurement probe. The transmitter unit converts the sensed signal to an optical signal which is transmitted through an optical medium to a receiver unit. Under control of a microprocessor, the level of the output signal from the transmitter unit is modulated by the signal received from the sensing probe. The microprocessor within the transmitter unit automatically controls the level of optical signal emitted by the optical converter, and further calibrates a driver circuit to maintain measurement accuracy.

Abstract: A linearized optical sampler is described. The optical sampler includes an electro-optic modulator having an optical signal input, an electrical signal input, and at least two optical signal outputs that generate at least two modulated optical signals. The optical sampler also includes at least two detectors each of which being optically coupled to a respective one of the at least two modulated optical signals. Each detector generates an electrical signal in response to an optical intensity of the respective one of the at least two modulated optical signals. The optical sampler also includes a signal processor electrically connected to each of the at least two detectors. The signal processor applies an inverse transform of the modulator transfer function. The signal processor also generates an electrical signal from the electrical signals generated by the detectors and from the inverse transform that is linearly related to an RF signal electrically that is coupled to the electrical signal input.

Abstract: The voltage transformer has a measuring element in the electrical field between an internal conductor and an external conductor of a metal-encapsulated, gas-insulated switchgear. The measuring element includes a Pockels crystal, a crystal of transparent material which, under the influence of the electric field, influences polarized light that is radiated through on account of the Pockels effect. The Pockels crystal has two parallel walls transverse with respect to the field lines. A first deflection prism, which deflects a light beam through 180.degree., is disposed on the crystal face at the high-voltage end. Several optical elements are disposed at the face on the low-voltage side. The optical elements include a light input coupler for polarized light and two light output couplers. The reflected light beam impinges on a beam splitter, which splits the light beam into two partial beams. The first partial beam radiates firstly through a quarter-wave plate and then through a first analyzer.

Abstract: A voltage and displacement sensitive probe with an electro-optic crystal, electrically conductive transparent films and adhered to a pair of parallel surfaces on the electro-optic crystal, a transparent elastic film which circumferential portion is bonded to the frame and which is symmetric with respect to any plane through the axis thereof, a probing needle bonded at its reflective bottom surface to the central portion on the film, a holder for holding the electro-optic crystal and the transparent elastic film via frame concentrically, a lead for grounding, and electrically conductive films for connecting between the films. Displacement detection of the probing needle is based upon the change in the length of the path of the light travelling through the electro-optic crystal being reflected by the surface and travelling in reverse direction. Voltage detection of the probing needle is based upon the phase difference between the two linearly-polarized light components.

Abstract: A beam of light is projected through an electrolyte to a SOI substrate to scan the surface of the SOI substrate. When the light passes through a pinhole in a buried oxide layer, the light excites a semiconductor layer beneath the buried oxides. An ammeter measures electric charges derived by this light excitation to indicate the presence of pinholes in the buried oxide.

Abstract: An apparatus and method for measuring instantaneous power using a magneto-optic Kerr effect sensor are disclosed. The apparatus comprises and the method requires a magneto-optic Kerr effect magnetic field sensing element and an optical system including a light source, first and second polarizers, and a photoconductive detector. In a preferred embodiment, the sensing element and the optical system are arranged to sense the intensity of a magnetic field generated by current passing through a high voltage power line so as to provide an optical signal that is representative of the current to the photoconductive detector. A voltage signal is tapped off of the high voltage power line to provide a bias signal to the photoconductive detector. The photoconductive detector thereby effectively multiplies the optical current signal with the voltage signal so as to provide a photoconductive detector current signal that is proportional to instantaneous power passing through the high voltage power line.

Abstract: A magnetic field sensor which can be used as an active antenna is disclosed that is capable of small size, ultrawideband operation, and high efficiency. The sensor includes a multiplicity of magnetic field transducers, e.g., superconducting quantum interference devices (SQUIDs) or Mach-Zehnder modulators, that are electrically coupled in a serial array. Dummy SQUIDs may be used about the perimeter of the SQUID array, and electrically coupled to the active SQUIDs for eliminating edge effects that otherwise would occur because of the currents that flow within the SQUIDs. Either a magnetic flux transformer which collects the magnetic flux and distributes the flux to the transducers or a feedback assembly (bias circuit) or both may be used for increasing the sensitivity and linear dynamic range of the antenna.

Abstract: A magnetometer uses a material exhibiting the Faraday effect, in which the polarization of light transmitted through the material is changed in response to a magnetic field. When the material is placed in a Fabry-Perot cavity, multiple reflections of the light within the Fabry-Perot cavity increase the change in polarization and thus the sensitivity of the magnetometer. Other effects that alter the polarization of light can be employed instead.

Abstract: An improved magneto optical current transducer for measuring electrical current is taught that significantly reduces birefringence resulting from thermal transients and construction-induced stresses. The transducer includes a housing made of a material that readily transfers heat throughout itself. Inside the housing and surrounding the magneto optical material is a buffer made of a material that does not readily tranfer heat from the housing to the magneto optical material, but rather slows its transference to that material material. The buffer material has a thermal expansion coefficient that is preferably very close to that of the magneto optical material, so that when the magneto optical material responds to changes in its temperature by expanding or contracting, the buffer expands with it at very nearly the same rate to avoid stresses.

Abstract: A laser probe for measuring a magnetic field is disclosed. A polarized laser beam is passed through a magneto-optic crystal in the presence of an unknown magnetic field. The rotation of the polarization which occurs through the magneto-optic crystal is measured in order to determine the magnitude of the magnetic field. The measured magnetic field is used to determine, for example, the current through a conductor such as an interconnect line on a semiconductor chip. A method of calibrating the magnetic field using a known magnetic from a solenoid is also disclosed. Further disclosed is a method of providing a zero-reference current by momentarily stopping the chip clock.

Abstract: A compact voltage sensor with stable characteristics is provided. A measuring beam that is incident from an optical fiber is branched into first and second modulation-inducing waveguides of a wave branching/combining section within an optical integrated circuit. Phase changes of opposite sign are induced in the measuring beams propagating within the first and second modulation waveguides by applying voltages of mutually opposite sign to modulation-inducing electrodes, to induce a phase difference between the two.

Abstract: A portion of a torsion bar (6) for axially supporting a movable plate (5) of a planar electromagnetic actuator, is made conducting by diffusing boron therein in a high concentration. An external power source can thus be electrically connected to a planar coil (7) via the torsion bar (6) itself. As a result, the possibility of disconnection faults in the electrical wiring due to back and forth twisting movement of the torsion bar is eliminated, thus improving the durability and reliability of the electromagnetic actuator.

Abstract: A radio-interrogated, surface-wave technology current transformer for high/medium-voltage systems includes a magnetosensitive element connected to a surface-wave structure of a surface-wave configuration as a termination of the surface-wave structure. A response signal of the surface-wave configuration is information regarding current strength/direction and phase of the current instantaneously flowing through the system, which is evaluated by a ground station. By virtue of the radio transmission, there is no electrical insulation problem, and the use of a radio-interrogated surface-wave configuration makes that part of the overall current transducer which is at high potential into a passive element of the same.