An electro-optical sensor comprises an optical input configured to receive an optical carrier via an upstream fiber. The electro-optical sensor also includes an optical modulator configured to modulate an electrical signal onto the optical carrier to create an optical signal. The electro-optical sensor further includes an optical output configured to transmit the optical signal via a downstream fiber. The electro-optical sensor employs a variation output configured to transmit variation data indicating variation in the received optical carrier to support compensation for corresponding variation in the optical signal.

An electro-optic modulator of a test and measurement system. The electro-optic modulator includes a first electrode, a second electrode with identical electrical characteristics as the first electrode and an optical waveguide between the first electrode and the second electrode. The first electrode and the second electrode present a balanced load to a device under test.

A sensor head of a test and measurement instrument can include an input configured to receive an input signal from a device under test (DUT), an optical voltage sensor having signal input electrodes and control electrodes or one set of electrodes, wherein the input is connected to the signal input electrodes, and a bias control unit connected to the control electrodes and configured to reduce an error signal or the input signal bias control signal are electrically combined and applied to a single set of electrodes.

In order to measure a voltage, an electro-optic element is placed in an electrical field generated by the voltage, and light is passed from a light source through a Faraday rotator and the electro-optic element onto a reflector and from there back through the electro-optic element and the Faraday rotator, thereby generating a voltage-dependent phase shift between two polarizations of the light. The interference contrast as well as a principal value of the total phase shift between said polarizations are measured and converted to a complex value having an absolute value equal to the contrast and a phase equal to the principal value. This complex value is offset and scaled using calibration values in order to calculate a compensated complex value. The voltage is derived from the compensated complex value.

An optical voltage prove includes: an optical modulator 1 having two modulation electrodes 11 and 12, the optical modulator 1 being configured to modulate an intensity of an incident light depending on a voltage between the two modulation electrodes and output the incident light which is modulated; an input/output optical fiber 2 connected with the optical modulator 1; two contact terminal attachment portions 5, 6 to which contact terminals 3, 4 can be detachably attached and contacted, the two contact terminals 3, 4 being configured to be in contact with the points to be measured, the two contact terminal attachment portions 5, 6 being respectively connected with the modulation electrodes 11, 12; and a package 8 that houses the optical modulator 1 and a part of the input/output optical fiber 2. A voltage signal induced via the contact terminals 3, 4 is converted into an optical intensity modulation signal. When an electric wave having a measurement frequency is applied while the contact terminal attachment portions 5, 6 are opened, the package 8 exhibits a shielding effect of attenuating the electric wave by 15 dB or more compared to an output signal intensity measured without providing the package.

An optical waveguide 1, an optical waveguide 2 are formed on a substrate 3 to be crossed with each other, modulator electrodes 11, 12, 13 and 14 are arranged along the optical waveguides 1, 2, and antennas 21, 22, 23, 24 (i.e., square patch antennas having an approximately same shape) are arranged around four corners of the square shape. The modulator electrode 11 is energized from the antenna 21 and the antenna 22, the modulator electrode 12 is energized from the antenna 24 and the antenna 23, the modulator electrode 13 is energized from the antenna 21 and the antenna 24, and the modulator electrode 14 is energized from the antenna 22 and the antenna 23. The light wave propagating through the optical waveguide 1 is modulated by an electric field of Y-direction, and the light wave propagating through the optical waveguide 2 is modulated by an electric field of X-direction.

Provided are a voltage measurement method and apparatus. The method includes following steps: a number j of height values are selected in a vertical direction of a transmission line, a number m of sensors used for measuring, according to a Stark effect, electric field strength of a corresponding spatial position are arranged in sequence at each of j spatial positions of the j heights from the ground, electric field strength values of the corresponding spatial position are measured through the m sensors respectively, and an electric field strength average value of the corresponding spatial position is calculated according to the acquired m electric field strength values, where j and m are positive integers, and the j spatial positions are below the transmission line; a voltage of the transmission line is calculated according to j electric field strength average values.

An electric field sensor includes a light source; an electro-optical crystal, a first separator, a first wavelength plate, first and second light receivers, a differential amplifier, and a controller. The electro-optical crystal has light from the light source incident thereon and receives an electric field generated by an object. The first separator separates light emitted from the electro-optical crystal into a P wave and an S wave. The first wavelength plate changes a phase of light at a pre-stage of the first separator. The first and second light receivers receive the P wave and S-wave light respectively, and convert the received light into first and second electrical signals, respectively. The differential amplifier generates a differential signal between the first and second electrical signals. The controller adjusts a wavelength of the light source such that an output value of a direct-current component of the differential amplifier is within a value range.

A semiconductor or integrated circuit block including a sense node and a converter circuit, in which the sense node develops a low frequency electrical parameter that is constant or varies at a frequency below a predetermined frequency level, and in which the converter circuit converts the low frequency electrical parameter into an alternating electrical parameter having a frequency at or above the predetermined frequency level sufficient to modulate a laser beam focused within a laser probe area of the converter circuit. The converter may include a ring oscillator, a switch circuit controlled by a clock enable signal, a capacitor having a charge rate based on the low frequency electrical parameter, etc. The laser probe area has a frequency level based on a level of the low frequency electrical parameter to modulate the reflected laser beam for measurement of the electrical parameter by a laser voltage probe test system.

Provided are a voltage measurement method and apparatus. The method includes following steps: a number j of height values are selected in a vertical direction of a transmission line, a number m of sensors used for measuring, according to a Stark effect, electric field strength of a corresponding spatial position are arranged in sequence at each of j spatial positions of the j heights from the ground, electric field strength values of the corresponding spatial position are measured through the m sensors respectively, and an electric field strength average value of the corresponding spatial position is calculated according to the acquired m electric field strength values, where j and m are positive integers, and the j spatial positions are below the transmission line; a voltage of the transmission line is calculated according to j electric field strength average values.