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.

According to an example aspect of the present invention, there is provided an electro-optic plasmonic device comprising: a slot waveguide that is defined by a first metallic electrode, a second metallic electrode and dielectric material in a slot between the first and second metallic electrodes. The device is configured to utilize the electric field induced Pockels effect.

A current-measuring transducer device has a current transducer for measuring an electric current along a conduction path. The current transducer has a magnetic field-sensitive element for converting the magnetic field resulting from the current flow along the conduction path into at least one physical variable and a measuring device for measuring the physical variable. The current transducer device has a coil arrangement with at least one coil for simulating the magnetic field resulting from the current flow along the conduction path. There is also described a method for calibrating a corresponding current transducer and a computer program product for performing the calibration method.

A system for measuring voltage includes a pulse-width modulator or voltage controlled oscillator (VCO) configured to receive an input voltage waveform from a DUT, and to output a pulse-width modulated (PWM) signal or frequency modulated (FM) signal mapped to the input voltage waveform, respectively; an optical transmitter configured to be modulated by the PWM signal or the FM signal to output an optical pulse signal having pulse widths corresponding to pulse widths of the PWM signal or equal to the frequency of the FM signal, respectively; an optical receiver configured to receive the optical pulse signal over an optical link and to convert the optical pulse signal to an electrical current; a transimpedance amplifier (TIA) configured to convert the electrical current to a voltage signal; and at least one filter or detection circuit configured to recover the input voltage waveform or provide numeric values corresponding to the input voltage waveform.

An optical fiber winding for measuring current circulating through a conductor. The optical fiber winding includes a first helically wound optical fiber cable and a second helically wound optical fiber cable. The first helically wound optical fiber cable is twisted about its longitudinal axis in a first twist direction, and the second helically wound optical fiber cable is twisted about its longitudinal axis in a second twist direction, the first twist direction being opposite the second twist direction. Each of the first and second helically wound optical fiber cables making contact with one another at multiple locations along their length. Due to the first and second helically wound optical fiber cables making contact with one another and being twisted in opposite directions, counteracting forces exist where the first and second helically wound optical fiber cables contact one another to resist an untwisting.

An optical fiber winding for measuring current circulating through a conductor. The optical fiber winding includes a first helically wound optical fiber cable and a second helically wound optical fiber cable. The first helically wound optical fiber cable is twisted about its longitudinal axis in a first twist direction, and the second helically wound optical fiber cable is twisted about its longitudinal axis in a second twist direction, the first twist direction being opposite the second twist direction. Each of the first and second helically wound optical fiber cables making contact with one another at multiple locations along their length. Due to the first and second helically wound optical fiber cables making contact with one another and being twisted in opposite directions, counteracting forces exist where the first and second helically wound optical fiber cables contact one another to resist an untwisting.

A magneto-optical sensor for sensing a current flowing through a conductor includes a light source capable of providing a linearly-polarised optical beam, and a polarisation analyser configured to perform a differential measurement of two polarisation components of the linearly-polarised optical beam having travelled along an optical path arranged between the light source and the polarisation analyser. The optical path forms a closed trajectory around the conductor. The sensor comprises a cell containing an atomic gas arranged along the optical path.

The following relates generally to optical voltage sensing, and in particular to optical voltage sensing of power grids and of a subject body. For example, some embodiments include an optical resonator comprising: (i) a top electrode layer, (ii) a piezoelectric layer, and (iii) a substrate. A light source may illuminate the optical resonator of the voltage sensor with light comprising an incident optical power at an input wavelength, where the input wavelength is offset from a resonant wavelength of the optical resonator by a baseline voltage. The applied voltage may then be measured by measuring a reflected or transmitted light power.

The present disclosure relates to the technical field of current sensors, and provides a fiber-optic current transformer based on nitrogen-vacancy (NV) centers in diamond, and a measurement method. The fiber-optic current transformer based on NV centers in diamond includes a device for laser light excitation and reflected light reception and analysis, a diamond NV center probe, a magnetic concentrator, and a microwave excitation device. The fiber-optic current transformer based on NV centers in diamond includes three measurement methods: an all-optical measurement method, a non-all-optical measurement method, and a measurement method combining the all-optical measurement method and the non-all-optical measurement method. A sensor in the present disclosure has advantages of a simple structure, strong practicability, resistance to external interference, and strong robustness.

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.