CN105486962A - Electric light crystal half-wave electric field and corresponding characteristic measuring apparatus and method - Google Patents

Abstract

The embodiment of the invention discloses a device and method for measuring the half-wave electric field and response characteristics of an electro-optic crystal, including a voltage generating device, a signal processing device, two identical metal plates, a laser source connected in sequence by an optical fiber, and a polarizer , an electro-optic crystal, a polarizer and a photodetector, the two metal plates are parallel in the horizontal direction and adhere to the upper and lower surfaces of the electro-optic crystal, one of the metal plates is grounded, the voltage generating device and Each of the signal processing devices is electrically connected to the other metal plate, and the photodetector is electrically connected to the signal processing device. The invention is used to measure the half-wave electric field and response characteristics of various electro-optic crystals, plays a very important role in the research of optical fiber voltage sensors, and provides important theoretical support for the material selection and size design of the sensors. The measuring method is direct and effective, the measuring device is easy to build, the structure is simple, and it is easy to popularize and apply.

Description

An electro-optic crystal half-wave electric field and corresponding characteristic measuring device and method

technical field

The invention relates to the technical field of voltage and electric field intelligent sensing, in particular to an electro-optic crystal half-wave electric field and a corresponding characteristic measuring device and method.

Background technique

Potential transformers have important applications in power systems and are one of the basic equipment for power system monitoring. With the increasing demand for electricity and the improvement of power quality in today's society, the power system is developing towards the trend of ultra/ultra high voltage and large capacity. However, the commonly used traditional electromagnetic voltage transformer has defects such as susceptibility to electromagnetic interference, complex insulation structure, high cost, bulky volume, ferromagnetic saturation and explosion hazard under high voltage conditions.

The fiber optic voltage sensor introduces optical devices as the sensing head of the primary part. There is no iron core and coil, and there is no electromagnetic coupling. Optical fiber is used as the transmission medium, which effectively overcomes the shortcomings of traditional electromagnetic voltage transformers. Compared with the traditional electromagnetic voltage transformer, it has the advantages of safety, reliability, stability, electromagnetic compatibility, wide frequency response, large dynamic range, no danger of fire and explosion, small size, and intelligence.

A core part of the fiber optic voltage sensor is the electro-optic crystal, which realizes the effective conversion between electrical signals and optical signals through the electro-optic crystal, and the selection of a suitable electro-optic crystal directly affects the working performance of the fiber optic voltage sensor. The research on materials and properties of electro-optic crystals is still in the development stage.

Contents of the invention

In the embodiment of the present invention, an electro-optic crystal half-wave electric field and corresponding characteristic measurement device and method are provided to solve the problem that the electro-optic crystal is not selected according to the material and properties of the electro-optic crystal in the prior art, which directly affects the working performance of the optical fiber voltage sensor question.

In order to solve the above technical problems, the embodiment of the present invention discloses the following technical solutions:

In the first aspect, the present invention provides an electro-optic crystal half-wave electric field and response characteristic measuring device, the device includes a voltage generating device, a signal processing device, two identical metal plates and a laser source connected in sequence by an optical fiber, A polarizer, an electro-optic crystal, a polarizer and a photodetector, the two metal plates are parallel in the horizontal direction and attached to the upper and lower surfaces of the electro-optic crystal, one of the metal plates is grounded, and the voltage Both the generating device and the signal processing device are electrically connected to the other metal plate, and the photodetector is electrically connected to the signal processing device.

Preferably, the measuring device also includes a height-adjustable insulating support and an optical vibration isolation platform, the electro-optic crystal and the metal plate are arranged on one end surface of the insulating support, the laser source, polarizer, insulating The pillar, the polarizer and the photodetector are fixedly arranged on the optical vibration isolation platform in sequence, and the centers of the laser source, the polarizer, the polarizer, the electro-optic crystal and the photodetector are located on the same horizontal line.

Preferably, the voltage generating device includes an arbitrary function voltage generator and a high-voltage amplifier, the output end of the arbitrary function voltage generator is connected to the input end of the high-voltage amplifier, and the output end of the high-voltage amplifier is connected to the positive pole of the metal plate electrical connection.

Preferably, the signal processing device includes a standard voltage divider and a multi-channel oscilloscope, the multi-channel oscilloscope is electrically connected to the output end of the photodetector, and the input end of the standard voltage divider is connected to the positive pole of the metal plate Electrically connected, the output terminal of the standard voltage divider is electrically connected with the multi-channel oscilloscope.

Preferably, the angle of the optical axis of the polarizer is 45°, the polarizer and the analyzer are arranged orthogonally to each other, and the polarizer and the analyzer are provided with quarter wave plate.

Preferably, the electro-optic crystal includes lithium niobate crystal.

On the other hand, the present invention also provides a method for measuring the half-wave electric field and response characteristics of an electro-optic crystal, comprising the following steps:

The output voltage of the voltage generating device forms an electric field at both ends of the electro-optic crystal;

The laser source outputs a laser beam, which is incident on the electro-optic crystal after passing through the polarizer, and the refractive index of the electro-optic crystal changes under the action of an external electric field, and an induced electro-optical axis appears;

Adjusting the optical axis angle of the polarizer so that the polarization plane of the incident laser light is 45° to the induction electro-optic axis;

The laser beam is modulated by an electric field into an optical signal, which is transmitted to the photodetector through an optical fiber;

The photodetector converts the light signal into a voltage signal, and outputs the voltage signal;

The signal processing device measures the received voltage signal, processes and displays the voltage signal.

Preferably, the voltage generating device outputs a voltage to form an electric field around the electro-optic crystal, including:

Adjust the arbitrary function voltage generator to output the required voltage waveform;

The output amplitude of the arbitrary function voltage generator and the amplification factor of the high-voltage amplifier are set to obtain the voltage at both ends of the electro-optic crystal.

Preferably, the signal processing device measures the received voltage signal, including:

Set the voltage division ratio of the standard voltage divider;

The actual applied voltage is monitored on a multi-channel oscilloscope and compared to the stated voltage signal.

It can be seen from the above technical solutions that an electro-optic crystal half-wave electric field and corresponding characteristic measurement method and device provided by the embodiment of the present invention, the electro-optic crystal half-wave electric field and corresponding characteristic measurement device include: a voltage generating device, a signal processing device, two identical The metal pole plate and the laser source, polarizer, electro-optic crystal, polarizer and photodetector sequentially connected by optical fiber, the two metal pole plates are parallel in the horizontal direction and close to the upper and lower surfaces of the electro-optic crystal, wherein One of the metal plates is grounded, the voltage generating device and the signal processing device are both electrically connected to the other metal plate, and the photodetector is electrically connected to the signal processing device.

The measurement method of the present invention comprises: the output voltage of the voltage generating device forms an electric field at both ends of the electro-optic crystal; the output laser beam of the laser source passes through the polarizer and is incident on the electro-optic crystal, and the refractive index of the electro-optic crystal changes under the action of an external electric field, and a Induction electro-optic axis; set the angle of the optical axis of the polarizer so that the polarization plane of the incident laser is 45° to the induction electro-optic axis; the laser beam is modulated by an electric field and transmitted to the photodetector through an optical fiber; the photodetector transmits the light The signal is converted into a voltage signal, and the voltage signal is output; the signal processing device measures the received voltage signal.

The invention is used to measure the half-wave electric field and response characteristics of various electro-optic crystals, plays a very important role in the research of optical fiber voltage sensors, and provides important theoretical support for the material selection and size design of the sensors. The measuring method is direct and effective, the measuring device is easy to build, the structure is simple, and it is easy to popularize and apply.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, In other words, other drawings can also be obtained from these drawings on the premise of not paying creative work.

Fig. 1 is a schematic structural diagram of an electro-optic crystal half-wave electric field and response characteristic measuring device provided by an embodiment of the present invention;

2 is a schematic diagram of the principle of an electro-optic crystal half-wave electric field and response characteristic measuring device provided by an embodiment of the present invention;

FIG. 3 is a schematic diagram of lateral modulation of an electro-optic crystal provided by an embodiment of the present invention;

Figure 1-Figure 3, symbols indicate:

1-Laser source, 2-Polarizer, 3-Analyzer, 4-Photodetector, 5-Insulation pillar, 6-Metal plate, 7-Arbitrary function voltage generator, 8-High voltage amplifier, 9-Multiple Channel oscilloscope, 10-standard voltage divider, 11-optical vibration isolation platform, 12-electro-optic crystal, 13-quarter wave plate.

detailed description

In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described The embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

Referring to Fig. 1, Fig. 1 is a schematic structural diagram of an electro-optic crystal half-wave electric field and response characteristic measuring device provided by an embodiment of the present invention, the device includes a voltage generating device, a signal processing device, and two identical metal plates 6 And the laser source 1, polarizer 2, electro-optic crystal 12, analyzer 3 and photodetector 4 connected in sequence by optical fiber, the two metal plates 6 are parallel in the horizontal direction and close to the electro-optic crystal 12 The upper and lower surfaces of the metal pole plate 6, wherein one of the metal pole plates 6 is grounded, the voltage generating device and the signal processing device are electrically connected to the other metal pole plate 6, and the photodetector 4 is connected to the signal processing device electrical connection.

The laser source 1 can emit parallel lasers of various wavelengths, the photodetector 4 can detect the optical power of lasers of various wavelengths, and convert it into a voltage signal that can be directly measured by an oscilloscope; the metal plate 6 The size of the electrode can be adjusted according to the size of the electro-optic crystal 12 to be tested, and the height between the plates can be adjusted.

The electro-optic crystal 12 in the present invention adopts lithium niobate crystal. Different electro-optic crystals 12 have different electro-optic effects under the same applied electric field. Selecting a lithium niobate crystal with an appropriate electro-optic coefficient can greatly improve the sensitivity of the sensor to sense the electric field while ensuring a large half-wave electric field.

The polarizer 2 is a device for obtaining polarized light from the natural light emitted by the laser source 1 . Commonly used polarizers 2 include polarizers, Nicol prisms, etc., and the polarizer 2 in the embodiment of the present invention is a polarizer.

Dichroic organic crystals, such as iodine quinine sulfate, tourmaline or polyvinyl alcohol film soaked in iodine solution, stretched at high temperature, dried, and then stuck between two glass plates to form a polarized piece. Polarized light is an artificial diaphragm, in which there are a large number of tiny grains arranged according to certain rules, which have the performance of selectively absorbing light vibrations in different directions, so that there is a special direction in the diaphragm, when a beam of natural light hits When it is on the diaphragm, the light vibration component perpendicular to this direction is completely absorbed, and only the light vibration component parallel to this direction passes through, thereby obtaining linearly polarized light. Polarizers only allow light in a certain direction to pass through. The polarization direction of the polarizer 2 in the present invention can be adjusted by 360°.

The analyzer 3 is made up of polarizers and is usually used in conjunction with the polarizer 2 . Polarizer 2 is used to make natural light, partially polarized light, etc. into linearly polarized light, and analyzer 3 is used to check whether a beam of light is polarized or not. The polarization direction of the analyzer 3 can be 360°.

As shown in FIG. 2 , FIG. 2 is a principle schematic diagram of an electro-optic crystal half-wave electric field and response characteristic measuring device provided by an embodiment of the present invention. The measuring device also includes a height-adjustable insulating support 5 and an optical vibration isolation platform 11, the electro-optic crystal 12 and the metal plate 6 are arranged on one end surface of the insulating support 5, the laser source 1, polarizer The laser source 1, polarizer 2, analyzer 3, electro-optic crystal 12 and The centers of the photodetectors 4 are located on the same horizontal line.

The highest withstand voltage level of the insulating support 5 is 60kV, and its height is adjustable; the size of the optical vibration isolation platform 11 is adjustable.

The voltage generating device comprises an arbitrary function voltage generator 7 and a high-voltage amplifier 8, the output of the arbitrary function voltage generator 7 is connected to the input of the high-voltage amplifier 8, and the output of the high-voltage amplifier 8 is connected to the metal plate The positive pole of 6 is electrically connected.

The arbitrary function voltage generator 7 can generate standard sine, triangle, square wave and various custom function waveforms, the frequency range is 0-1GHz, and the amplitude range is 0-100V; the high-voltage amplifier 8 can convert the input voltage amplitude The value is magnified by a factor of 5000.

The signal processing device includes a standard voltage divider 10 and a multi-channel oscilloscope 9, the multi-channel oscilloscope 9 is electrically connected to the output end of the photodetector 4, and the input end of the standard voltage divider 10 is connected to the metal plate 6, the output end of the standard voltage divider 10 is electrically connected to the multi-channel oscilloscope 9.

The voltage division ratio of the standard voltage divider 10 is adjustable; each channel of the multi-channel oscilloscope 9 has an independent trigger function, and the sampling rate is 200MHz.

In the electro-optic crystal half-wave electric field and response characteristic measuring device provided by the embodiment of the present invention, the angle of the optical axis of the polarizer 2 is 45°, and the polarizer 2 and the analyzer 3 are placed in a positive direction to each other. A quarter-wave plate 13 is arranged between the polarizer 2 and the analyzer 3 to adjust the delay of the intrinsic phase.

The quarter wave plate 13 is a birefringent single crystal sheet with a certain thickness. When light is incident on the normal direction, the phase difference between ordinary light (o light) and extraordinary light (e light) is equal to π/2 or its odd multiple, such a wafer is called a quarter wave plate. When the linearly polarized light is vertically incident on the quarter-wave plate 13, and the polarization of the light is at an angle of θ with the optical axis plane (vertical natural split surface) of the mica, it becomes elliptically polarized light after exiting, especially when θ=45°, The outgoing light is circularly polarized light.

Lithium niobate crystal is a uniaxial crystal, and different combinations of light transmission direction and voltage direction will lead to differences in the effect of electro-optic modulation. Two typical modulation methods are lateral modulation and longitudinal modulation.

For the measurement of low voltage, lateral modulation is more advantageous because the induction sensitivity can be adjusted by changing the crystal size, so the present invention uses lateral modulation to detect the electro-optic crystal 12, as shown in Figure 3, which is the embodiment of the present invention A schematic diagram of lateral modulation of an electro-optic crystal provided in the embodiment. A lithium niobate crystal is placed between two polarizers 2 and an analyzer 3 that are orthogonal to each other, and transverse modulation is adopted. The optical axis (z-axis) direction of the electro-optic crystal 12 is 45° to the polarization direction and passes through the niobium A quarter-wave plate 13 is added between the lithium acid crystal and the polarizer 2 to adjust the inherent phase delay

As shown in Fig. 1, an electro-optic crystal half-wave electric field and response characteristic measuring device provided by the embodiment of the present invention is designed based on the principle of primary electro-optic effect. Under the influence of the electric field, birefringence occurs, which leads to a phase difference between the ordinary light and the extraordinary light in the emitted laser light. The change of the phase difference can be converted into an intuitively visible change of the laser light power through the analyzer 3, which can be monitored. The crystal 12 is subjected to the action of the externally applied electric field, so as to study its various electro-optical characteristics.

Corresponding to the embodiment of the device for measuring the half-wave electric field and response characteristics of the electro-optic crystal provided by the present invention, the present invention also provides a method for measuring the half-wave electric field and response characteristics of the electro-optic crystal. Include the following steps:

Step S101: The voltage generating device outputs a voltage to form an electric field at both ends of the electro-optic crystal 12 .

Wherein, this step also includes adjusting the arbitrary function voltage generator 7 to output the required voltage waveform; setting the output amplitude of the arbitrary function voltage generator 7 and the amplification factor of the high voltage amplifier 8 to obtain the voltage at both ends of the electro-optic crystal 12 .

Step S102: The laser source 1 outputs a laser beam, which passes through the polarizer 2 and is incident on the electro-optic crystal 12. The refractive index of the electro-optic crystal 12 changes under the action of an external electric field, and an induced electro-optical axis appears.

Step S103: Adjust the angle of the optical axis of the polarizer 2 so that the polarization plane of the incident laser light is 45° from the induction electro-optic axis.

Step S104: The laser beam is modulated by an electric field, and transmitted to the photodetector 4 through an optical fiber.

Step S105: the photodetector 4 converts the light signal into a voltage signal, and outputs the voltage signal.

Step S106: The signal processing device measures the received voltage signal, and processes and displays the voltage signal.

This step also includes: setting the voltage division ratio of the standard voltage divider 10; monitoring the actual applied voltage on the multi-channel oscilloscope 9, and comparing it with the voltage signal.

It can be seen from the method for measuring the half-wave electric field and response characteristics of the electro-optic crystal provided by the above-mentioned embodiments of the present invention that the externally applied voltage waveform and voltage level are reasonably selected according to the actual parameters of the electro-optic crystal 12 to be tested and the specific needs of the test, and at the same time, the insulating support is reasonably set 5 height and safe distance for operation; adjust the arbitrary function voltage generator 7 to make it output the voltage waveform required for the test; reasonably set the magnification of the high-voltage amplifier 8 and the output amplitude of the arbitrary function voltage generator 7 to obtain the voltage applied to both ends of the electro-optic crystal 12 Required voltage; reasonably set the voltage division ratio of the standard voltage divider 10, monitor the actual applied voltage, and realize the comparison with the output signal of the photodetector 4, thereby realizing the response characteristics of the electro-optic crystal 12 to be measured and the half-wave electric field. Measurement.

It should be noted that in this article, relative terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply these No such actual relationship or order exists between entities or operations. Furthermore, the term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus comprising a set of elements includes not only those elements, but also includes elements not expressly listed. other elements of or also include elements inherent in such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article or apparatus comprising said element.

The above descriptions are only specific embodiments of the present invention, so that those skilled in the art can understand or implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (9)

1. an electro-optic crystal half-wave electric field and response characteristic measurement device, it is characterized in that, comprise: voltage generation circuit, signal processing apparatus, two identical metal polar plates (6) and the lasing light emitter (1) be connected successively by optical fiber, the polarizer (2), electro-optic crystal (12), analyzer (3) and photodetector (4), parallel in two described metal polar plate (6) horizontal directions, and be adjacent to the upper and lower surface of described electro-optic crystal (12), metal polar plate described in one of them (6) ground connection, described voltage generation circuit and described signal processing apparatus are all electrically connected with metal polar plate described in another (6), described photodetector (4) is electrically connected with described signal processing apparatus.

2. electro-optic crystal half-wave electric field according to claim 1 and response characteristic measurement device, it is characterized in that, described measurement mechanism also comprises adjustable for height insulation column (5) and optics vibration-isolating platform (11), described insulation column (5) end face arranges described electro-optic crystal (12) and described metal polar plate (6), described lasing light emitter (1), the polarizer (2), insulation column (5), analyzer (3) and photodetector (4) are fixedly installed on described optics vibration-isolating platform (11) successively, and described lasing light emitter (1), the polarizer (2), analyzer (3), being centrally located on same level line of electro-optic crystal (12) and photodetector (4).

3. electro-optic crystal half-wave electric field according to claim 1 and response characteristic measurement device, it is characterized in that, described voltage generation circuit comprises arbitrary function voltage generator (7) and high-voltage amplifier (8), described arbitrary function voltage generator (7) output terminal is connected with described high-voltage amplifier (8) input end, and described high-voltage amplifier (8) output terminal is electrically connected with the positive pole of described metal polar plate (6).

4. electro-optic crystal half-wave electric field according to claim 1 and response characteristic measurement device, it is characterized in that, described signal processing apparatus comprises standard voltage divider (10) and hyperchannel oscillograph (9), described hyperchannel oscillograph (9) is electrically connected with described photodetector (4) output terminal, described standard voltage divider (10) input end is electrically connected with the positive pole of described metal polar plate (6), and described standard voltage divider (10) output terminal is electrically connected with described hyperchannel oscillograph (9).

5. electro-optic crystal half-wave electric field according to claim 1 and response characteristic measurement device, it is characterized in that, the logical optical axis angle of the described polarizer (2) is 45 °, the described polarizer (2) and described analyzer (3) in orthogonal setting, and are provided with quarter-wave plate (13) between the described polarizer (2) and described analyzer (3).

6. electro-optic crystal half-wave electric field according to claim 1 and response characteristic measurement device, is characterized in that, described electro-optic crystal (12) comprises lithium columbate crystal.

7. electro-optic crystal half-wave electric field and a response characteristic measurement method, is characterized in that, comprise the following steps:

Voltage generation circuit output voltage, forms electric field at electro-optic crystal (12) two ends;

Lasing light emitter (1) Output of laser light beam, by being incident on described electro-optic crystal (12) after the polarizer (2), there is induced electrooptic axis in described electro-optic crystal (12) variations in refractive index under outside electric field action;

Adjust the logical optical axis angle of the described polarizer (2), make the plane of polarization of incident laser and described induced electrooptic axis at 45 °;

Laser beam becomes light signal through described Electric Field Modulated, is sent to photodetector (4) by optical fiber;

Described light signal is converted to voltage signal by described photodetector (4), and exports described voltage signal;

The described voltage signal that signal processing apparatus measurement receives, and to described voltage signal process and display.

8. electro-optic crystal half-wave electric field according to claim 7 and response characteristic measurement method, is characterized in that, described voltage generation circuit output voltage, forms electric field, comprising around electro-optic crystal (12):

Regulate arbitrary function voltage generator (7), export required voltage waveform;

Described arbitrary function voltage generator (7) output amplitude and high-voltage amplifier (8) enlargement factor are set, obtain the voltage at described electro-optic crystal (12) two ends.

9. electro-optic crystal half-wave electric field according to claim 7 and response characteristic measurement method, is characterized in that, the voltage signal that described signal processing apparatus measurement receives, and comprising:

The intrinsic standoff ratio of standard voltage divider (10) is set;

At the actual applied voltage of the upper monitoring of hyperchannel oscillograph (9), and contrast with voltage signal.