Design and optimization of a low-frequency electric field sensor using Pockels effect (original) (raw)
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Investigation the Performance of Electro-Optical AC Voltage LiNbO3 Sensor Based on Pockels Effect
Tikrit Journal of Engineering Science, 2013
In contrast to conventional voltage sensor technology (e.g., inductive voltage transformers or capacitive voltage transformers), optical sensors have inherent and advantageous features, such as wider bandwidth, larger dynamic range and lighter weight. The aim of this work is to implement an AC voltage sensor based on Pockels electro-optic effect in LiNbO 3 crystal. The research has been conducted in two ways .The first way is the installation tested uses external electrodes and a He-Ne laser as a light source, whereas the second way is by using the direct voltage application to the metalized sides of the LiNbO 3 crystal built into an optic cell. Results of both tests shows that by using the direct voltage application to the metalized sides of the LiNbO 3 crystal built into an optic cell led to better repeatability of voltage measurements and corresponds to more realistic conditions.
Sensor Based on Pockels Effect
2014
In contrast to conventional voltage sensor technology (e.g., inductive voltage transformers or capacitive voltage transformers), optical sensors have inherent and advantageous features, such as wider bandwidth, larger dynamic range and lighter weight. The aim of this work is to implement an AC voltage sensor based on Pockels electro-optic effect in LiNbO3 crystal. The research has been conducted in two ways .The first way is the installation tested uses external electrodes and a He-Ne laser as a light source, whereas the second way is by using the direct voltage application to the metalized sides of the LiNbO3 crystal built into an optic cell. Results of both tests shows that by using the direct voltage application to the metalized sides of the LiNbO3 crystal built into an optic cell led to better repeatability of voltage measurements and corresponds to more realistic conditions.
Sensitivity enhancements to photonic electric field sensor
Enabling Photonic Technologies for Aerospace Applications VI, 2004
This paper describes an electrode-less, all-optical, wideband electric field sensor fabricated in an electro-optic lithium niobate substrate. The sensor component is an integrated optic Mach-Zehnder interferometer. The electric field sensor uses the electro-optic properties of lithium niobate to modulate the phase of the light propagating in each arm of the Mach-Zehnder interferometer. The phase modulated light is then converted to intensity modulation at the output of the interferometer. The unique feature of the sensor device is that the orientation of the crystal in one arm of the Mach-Zehnder interferometer is inverted to provide push-pull optical modulation for an applied electric field. Optical fibers are connected to the input and output of the sensor device. The basic device is an all-dielectric intensity modulator. The ability to operate the sensor without the use of any metal antenna permits its use in extremely high field conditions without any danger of damaging the sensor. The optical fiber connections provide optical isolation to the instrumentation to protect the instrumentation from possible overload conditions. The electrode-less sensor is designed specially for measuring high field strengths similar to the conditions in electromagnetic pulse, high power microwave and high voltage power lines. Sensitivity improvements are possible by using carrier suppression techniques.
Sensitivity enhancements to photonic electric field sensor
2004
This paper describes an electrode-less, all-optical, wideband electric field sensor fabricated in an electro-optic lithium niobate substrate. The sensor component is an integrated optic Mach-Zehnder interferometer. The electric field sensor uses the electro-optic properties of lithium niobate to modulate the phase of the light propagating in each arm of the Mach-Zehnder interferometer. The phase modulated light is then converted to intensity modulation at the output of the interferometer. The unique feature of the sensor device is that the orientation of the crystal in one arm of the Mach-Zehnder interferometer is inverted to provide push-pull optical modulation for an applied electric field. Optical fibers are connected to the input and output of the sensor device. The basic device is an all-dielectric intensity modulator. The ability to operate the sensor without the use of any metal antenna permits its use in extremely high field conditions without any danger of damaging the sensor. The optical fiber connections provide optical isolation to the instrumentation to protect the instrumentation from possible overload conditions. The electrode-less sensor is designed specially for measuring high field strengths similar to the conditions in electromagnetic pulse, high power microwave and high voltage power lines. Sensitivity improvements are possible by using carrier suppression techniques.
Response Analysis of Electro-Optic Electric Field Sensor
Tikrit Journal of Engineering Sciences
In this paper an electric field sensor based on the electro-optical effect in Lithium Niobate crystal is studied. The electro-optically induced polarization modification in crystal has been described and the response analyzed for different crystal lengths and light source wave lengths. The study shows that as the crystal length increased the required electric field to produce a phase-shift equal is decreased. The responsivity of the sensor for different ranges of the electric field to be measured has been calculated and it is found that the rate of change of the half of the phase shift with respect to the electric field d(/2)/dE is equal to the responsivity of the sensor at the mid-point of the linear part of the light intensity response curve.
Lithium niobate sensor for measurement of DC electric fields
IEEE Transactions on Instrumentation and Measurement, 2001
The paper presents a theoretical analysis and experimental verification of a lithium niobate electrooptic sensor for measurement of dc electric fields in a space charge environment. Both unipolar and bipolar charge environments were investigated. In both cases the sensor output is linearly dependent on the measured electric field and independent of the density of space charge. Temperature stability of the sensor was analyzed and a novel compensation model is proposed.
Review of Scientific Instruments, 1997
A novel system is presented which is capable of measuring with high accuracy the linear ͑Pockels͒ electro-optic effect by means of a new dynamic ͑ac͒ method. This method is based on the observation of the photodetected output obtained from a Senarmont-type ellipsometric system with an ac ͑modulating͒ voltage being applied onto the electro-optic sample under test. This observation is made on a high sensitivity oscilloscope and allows us to determine accurately the null point of the system by locating the position of the analyzer that produces in the output a characteristic and abrupt doubling of the ͑modulation͒ frequency. By locating this frequency doubling position without and with electric field one can finally determine the corresponding electro-optic coefficients. Theoretical analysis and considerations of practical interest are presented in the article and show that the system in question can ensure reduced errors and increased sensitivity. Also, experimental evidence in support of the expected performance is obtained by implementing and applying the system for the measurement of the composite electro-optic coefficient r c of LiNbO 3 for various temperatures in the range of 17-20°C.
Electric Field Sensing Scheme Based on Matched $ \hbox{LiNbO}_{3}$ Electro-Optic Retarders
IEEE Transactions on Instrumentation and Measurement, 2008
In this paper, a wideband-electric-field-sensing scheme that uses optically matched integrated optics electrooptic devices and coherence modulation of light is described. In a coherence modulation scheme, the integrated optics sensor detects the electric field and imprints it around an optical delay. The optical delay is generated by a birefringent optical waveguide in a lithium niobate (LiNbO 3 ) integrated optics two-wave interferometer. The modulated optical delay, acting as an information carrier, is transmitted through an optical fiber channel. At the receiver, light is demodulated by a second integrated optics two-wave interferometer, which also introduces a second optical delay. The optical delays on the sensor and demodulator are matched at the same value. The integrated optics demodulator measures the autocorrelation of light around the optical delay value, and the imprinted electric field is recuperated as a linear variation of the received optical power. The matching of the sensor and demodulator allows a direct detection of the electric field, giving a unique feature to this fiber-integrated optics scheme. The experimental setup described here uses two pigtailed LiNbO 3 electrooptic crystals: one acting as the electric field sensor and the other acting as the optical demodulator. The wideband sensing range on the experimental setup corresponds to frequencies between 0 and 20 kHz.
Computer simulation of the fiber optic electric field sensor
Journal of Physics: Conference Series, 2019
The article describes an approach for simulating the fiber optic electric field sensor with a sensitive element operating on the Pockels effect arising in an optical waveguide recorded in a lithium niobate crystal. The sensor simulating was implemented in the NI LabVIEW programming environment and built using a mathematical apparatus based on the formalism of Jones matrices, which allowed to describe the polarization state of the light beam at the output of the sensor and to calculate the intensity of the interference signal at the photodetector input. Besides, additional modulation with a sawtooth signal and digital phase detection were used in the simulation. The sensor model described in the article can be easily modified and complicated, which makes it possible to use it for research and analysis of both parasitic effects and different optical sensor configurations.