초록 ▼

A small sized electro-optic voltage sensor capable of accurate measurement of high levels of voltages without contact with a conductor or voltage source is provided. When placed in the presence of an electric field, the sensor receives an input beam of electromagnetic radiation into the sensor. A po

A small sized electro-optic voltage sensor capable of accurate measurement of high levels of voltages without contact with a conductor or voltage source is provided. When placed in the presence of an electric field, the sensor receives an input beam of electromagnetic radiation into the sensor. A polarization beam displacer serves as a filter to separate the input beam into two beams with orthogonal linear polarizations. The beam displacer is oriented in such a way as to rotate the linearly polarized beams such that they enter a Pockels crystal at a preferred angle of 45 degrees. The beam displacer is therefore capable of causing a linearly polarized beam to impinge a crystal at a desired angle independent of temperature. The Pockels electro-optic effect induces a differential phase shift on the major and minor axes of the input beam as it travels through the Pockels crystal, which causes the input beam to be elliptically polarized. A reflecting prism redirects the beam back through the crystal and the beam displacer. On the return path, the polarization beam displacer separates the elliptically polarized beam into two output beams of orthogonal linear polarization representing the major and minor axes. In crystals that introduce a phase differential attributable to temperature, a compensating crystal is provided to cancel the effect of temperature on the phase differential of the input beam. The system may include a detector for converting the output beams into electrical signals, and a signal processor for determining the voltage based on an analysis of the output beams. The output beams are amplitude modulated by the frequency of the electric field and the amplitude of the output beams is proportional to the magnitude of the electric field, which is related to the voltage being measured.

대표청구항 ▼

[ We claim:] [24.]24. A system, in an environment having a voltage and an electric field, for measuring the voltage, the system comprising:a detector comprising:a light source for generating an input beam; anda first and second photo detector for receiving a first and second output beam; anda sensor

[ We claim:] [24.]24. A system, in an environment having a voltage and an electric field, for measuring the voltage, the system comprising:a detector comprising:a light source for generating an input beam; anda first and second photo detector for receiving a first and second output beam; anda sensor operably connected to the detector, the sensor comprising:a Pockels crystal for receiving a first component of the input beam,wherein the Pockels crystal is oriented in the electric field such that the first component experiences a phase differential to produce an elliptically polarized output beam;a compensating crystal shielded from the electric field and optically connected to the Pockels crystal, the compensating crystal possessing optical properties substantially identical to the Pockels crystal and rotated approximately 90 degrees with respect to the Pockels crystal such that a portion of the phase differential attributable to temperature variations is eliminated; anda beam displacer optically connected to the compensating crystal and oriented at an angle with respect to the compensating crystal, wherein the beam displacer:receives the input beam from the light source and separates the input beam into the first and second components, wherein the first and second components are orthogonal and the first component impinges the compensating crystal at the angle; andreceives the elliptically polarized output beam from the compensating crystal and separates the elliptically polarized output beam into the first and second output beams which represent a major axis and a minor axis of the elliptically polarized output beam; anda signal processor for receiving at least one signal from the first and second photo detectors, wherein the signal processor computes the voltage from the at least one signal.