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.

A current sensor of a detection target current using a shunt resistor includes: a resistance value correction circuit having: a correction resistor; a signal application unit that applies an alternating current signal to a series circuit of the shunt resistor and the correction resistor; a first voltage detection unit that detects the terminal voltage of the shunt resistor; a second voltage detection unit that detects a terminal voltage of the correction resistor; and a correction unit that calculates the resistance value of the shunt resistor based on a first voltage detection value by the first voltage detection unit and a second voltage detection value by the second voltage detection unit, and corrects the resistance value for current detection based on a calculated resistance value of the shunt resistor.

A glass ring for current measurements includes a glass body, which can be disposed around an electrical conductor and has a light entry surface and a light exit surface. The glass ring allows light which enters the glass body through the light entry surface to circulate completely around the conductor in the glass body by reflection on external sides or outer faces of the glass body, the light exiting from the glass body on the light exit surface. The glass ring is formed of a monolithic glass body. A method for optical current measurement includes using a current flow in an electrical conductor to generate an electromagnetic field around the conductor, by which a polarization of a light beam in the glass ring around the conductor, in particular with a plane perpendicular to the longitudinal axis of the conductor, is changed as the light beam circulates around the conductor.

Disclosed is an optical fiber winding for measuring the current circulating through a conductor. According to one embodiment the optical fiber winding includes a central support core extending in a longitudinal direction, a first optical fiber cable arranged around the central support core, a second optical fiber cable arranged around the central support core, the first and second optical fiber cables extend in a helical manner around the central support core. According to one embodiment the first optical fiber cable is twisted about its longitudinal axis in a first twist direction, and the second optical fiber cable is twisted about its longitudinal axis in a second twist direction, the first twist direction being opposite the second twist direction. Optical fiber-based current measuring equipment is also disclosed.

To provide a magnetic sensor element and a magnetic sensor device that can be easily manufactured and can reduce a loss of light to the extent possible. The above-described problem is solved by a magnetic sensor element comprising a planar lightwave circuit (11) provided with a light branching part (12), an input optical fiber (19) and an output optical fiber (20) connected to the planar lightwave circuit (11), a metal magnetic body type light transmitting film (30) that is provided on one end surface of the planar lightwave circuit (11) and transmits light entered from the input optical fiber (19), and a reflecting film (40) that is provided on the metal magnetic body type light transmitting film (30) and reflects the transmitted light. The output optical fiber (20) is a polarization-plane maintaining optical fiber, and the input optical fiber (19) and the output optical fiber (20) are aligned and connected to the planar lightwave circuit (11).

To provide a magnetic sensor element and a magnetic sensor device that can be easily manufactured and can reduce a loss of light to the extent possible. The above-described problem is solved by a magnetic sensor element comprising a planar lightwave circuit (11) provided with a light branching part (12), an input optical fiber (19) and an output optical fiber (20) connected to the planar lightwave circuit (11), a metal magnetic body type light transmitting film (30) that is provided on one end surface of the planar lightwave circuit (11) and transmits light entered from the input optical fiber (19), and a reflecting film (40) that is provided on the metal magnetic body type light transmitting film (30) and reflects the transmitted light. The output optical fiber (20) is a polarization-plane maintaining optical fiber, and the input optical fiber (19) and the output optical fiber (20) are aligned and connected to the planar lightwave circuit (11).

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 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.

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.

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.