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 sensor assembly that senses current in a secondary electrical cable while sensing voltage in a primary electrical cable. The optical sensor assembly may include a sensor body, a concentrator core for measuring current. The concentrator core may be attached to a first end of the sensor body. The optical sensor assembly may include a plurality of extension arms that extend from the sensor body. The extension arms may include clamping devices on one end that are configured to attach to a first electrical cable. The concentrator core may be configured to at least partially surround a second electrical cable and sense the current from that second electrical cable.

An optical voltage sensor assembly includes an input fiber-optic collimator positioned and configured to collimate input light beam from a light source. A crystal material is positioned to receive the input light beam from the light source and configured to exhibit the Pockels effect when an electric field is applied through the crystal material. An output fiber-optic collimator is positioned to receive an output light beam from the crystal material and configured to focus the output light beam from the crystal onto a detector. Methods of using the optical voltage sensor assembly are also disclosed.

An inspection apparatus includes a tester unit that applies a stimulus signal to a semiconductor apparatus, an MO crystal arranged to face a semiconductor apparatus, a light source that outputs light, an optical scanner that irradiates the MO crystal with light output from light source, a light detector that detects light reflected from the MO crystal arranged to face the semiconductor apparatus D and outputs a detection signal, and a computer that generate phase image data based on a phase difference between a reference signal generated based on a stimulus signal and the detection signal, the phase image data including a phase component indicating the phase difference, and generates an image indicating a path of a current from the phase image data.

Methods and systems are disclosed for sensing an environment electric field. In one exemplary implementation, a method includes disposing a sensor in the environment, wherein the sensor comprising a crystalline lattice and at least one optically-active defect in the crystalline lattice; pre-exciting the crystalline lattice to prepare at least one defect in a first charge state using a first optical beam at a first optical wavelength; converting at least one defect from the first charge state to a second charge state using a second optical beam at a second optical wavelength; monitoring a characteristics of photoluminescence emitted from the defect during or after the conversion of the at least one defect from the first charge state to the second charge state; and determining a characteristics of the electric field in the environment according to the monitored characteristics of the photoluminescence.

Methods and systems are disclosed for sensing an environment electric field. In one exemplary implementation, a method includes disposing a sensor in the environment, wherein the sensor comprising a crystalline lattice and at least one optically-active defect in the crystalline lattice; pre-exciting the crystalline lattice to prepare at least one defect in a first charge state using a first optical beam at a first optical wavelength; converting at least one defect from the first charge state to a second charge state using a second optical beam at a second optical wavelength; monitoring a characteristics of photoluminescence emitted from the defect during or after the conversion of the at least one defect from the first charge state to the second charge state; and determining a characteristics of the electric field in the environment according to the monitored characteristics of the photoluminescence.

The invention enables an optical voltage sensor, comprising a piezoelectric actuator mechanically coupled to an optical strain sensor (such as a fibre Bragg grating), to withstand lightning impulses, the effects of which would otherwise be harmful or destructive to the piezoelectric actuator and/or other sensitive components. As such, the optical voltage sensor, comprised within a photonic voltage transducer which also comprises a lightning impulse attenuator, is able to comply with relevant standards and be used for applications in power networks and exposed to the highest voltages for equipment.

Provided is an integrated optical system-based optical current sensor system comprising a light source generating reference light for current or magnetic field sensing, a polarizer for polarizing the reference light, a phase modulator for phase-modulating the polarized light into a predetermined reference signal, and a Faraday rotation reflector for reflecting the light propagated through an optical path at the end of the optical fiber, wherein the invention further comprises a plurality of pig-tailed optical fiber blocks in which the optical fibers are accommodated therein, and an integrated optical system composed of a plurality of optical components optically bonded to the pig-tailed blocks at interfaces with the pig-tailed blocks.

Passive optical Sagnac interferometers for current sensing, method of using the same and method of constructing the same. In one embodiment, the passive optical Sagnac interferometer for current sensing comprises an NN fibre coupler, wherein N>=3; and a fibre coil disposed on a first side of the NN fibre coupler, a first port of the NN fibre coupler coupled to a first end of the fibre coil via a first linear polariser and a second port of the NN fibre coupler coupled to a second end of the fibre coil via a second linear polariser; wherein the fibre coil is configured to support only one elliptical polarisation state in counter-propagating light signals in the fibre coil.

Passive optical Sagnac interferometers for current sensing, method of using the same and method of constructing the same. In one embodiment, the passive optical Sagnac interferometer for current sensing comprises an NN fibre coupler, wherein N>=3; and a fibre coil disposed on a first side of the NN fibre coupler, a first port of the NN fibre coupler coupled to a first end of the fibre coil via a first linear polariser and a second port of the NN fibre coupler coupled to a second end of the fibre coil via a second linear polariser; wherein the fibre coil is configured to support only one elliptical polarisation state in counter-propagating light signals in the fibre coil.