A measuring device and method for measuring piezoceramic modulators

Abstract

The application discloses a kind of measuring device and method for measuring piezoelectric ceramic modulator, comprising: narrow linewidth laser for generating stable laser, the laser is as input light, inject into first optical fiber coupler;The output end of first optical fiber coupler is connected with the piezoelectric ceramic modulator to be measured and the optical fiber delay line respectively;The optical signal output by first optical fiber coupler is output to the piezoelectric ceramic modulator to be measured and the optical fiber delay line respectively;The output end of the piezoelectric ceramic modulator to be measured and the optical fiber delay line are connected with the input end of second optical fiber coupler;The optical fiber signal output by the piezoelectric ceramic modulator to be measured and the optical fiber delay line is injected into second optical fiber coupler;The output end of second optical fiber coupler is connected with optical oscilloscope.The problem of the performance measurement absence of existing piezoelectric ceramic modulator is solved.

Description

Technical Field

[0001] This invention relates to the field of piezoelectric ceramic performance measurement, and more specifically to a measuring device and method for measuring piezoelectric ceramic modulators. Background Technology

[0002] With the development of power systems, current transformers, as crucial equipment, directly impact the safety of power system operation and the economic benefits of the power grid through their stability and accuracy. Traditional electromagnetic current transformers can only meet the basic requirements for AC current measurement but cannot measure changes in DC current. In recent years, fiber optic current transformers based on the Faraday effect have been able to directly measure DC current and have attracted widespread attention due to their advantages such as resistance to electromagnetic interference, high temperature resistance, and corrosion resistance, and have already been implemented in industrial applications.

[0003] In current all-fiber current transformers, the tubular or ring-shaped piezoelectric ceramic modulator is a key component of the optical transmission path and plays a crucial role. The optical signal carrying Faraday modulation information, after passing through the piezoelectric ceramic modulator, generates a series of high-order harmonics based on the modulation frequency. By processing these harmonics, the measured current value can be directly obtained. Therefore, the performance of the piezoelectric ceramic directly affects the accuracy of the measurement data. Currently, many manufacturers produce piezoelectric ceramics, with varying material types and structural dimensions. Therefore, measuring the parameters of piezoelectric ceramic tubes from different manufacturers, using different materials, and from different batches is a fundamental task in the fabrication of piezoelectric ceramic modulators. Furthermore, variations in the tightness and length of the optical fiber wound around the piezoelectric ceramic will affect the performance consistency of the all-fiber current transformer. Therefore, measuring the performance of piezoelectric ceramic modulators wound with optical fibers is of great significance for the production and use of fiber optic current transformers.

[0004] Furthermore, the temperature characteristics and vibration resistance of piezoelectric ceramics have a significant impact on the environmental adaptability of all-fiber current transformers. Therefore, measuring the performance of piezoelectric ceramics at different temperatures and in vibrating environments is an important research topic for the development, production, and use of all-fiber current transformers.

[0005] Although piezoelectric ceramics have many parameters, the most important one is their piezoelectric strain coefficient (or piezoelectric coefficient) d33. Certain methods exist for measuring the piezoelectric coefficient of materials.

[0006] The traditional method for testing piezoelectric coefficient involves the instrument emitting an electrical drive signal, which causes the electromagnetic drive component inside the test head to generate a low-frequency alternating force of less than 1 Newton. This force is applied to the test sample and an internal comparison sample through the upper and lower probes. Since the two samples are mechanically connected in series, the alternating forces they experience are equal. The two piezoelectric signals generated by the positive piezoelectric effect are then processed by the instrument to display their d33 value and polarity.

[0007] Another device for measuring the piezoelectric coefficient d33 of piezoelectric ceramics works by applying pressure to the sample and measuring the resulting charge. To obtain accurate piezoelectric material parameters, the measurement system employs phase-locked charge amplification technology to significantly suppress unwanted noise and improve the signal-to-noise ratio, thus obtaining a more accurate d33 value.

[0008] Although the above methods are mature, they can only measure the parameters of piezoelectric ceramics, not the parameters of piezoelectric ceramic modulators. Their application scenarios are somewhat different from those of all-fiber current transformers. Currently, there is no dedicated device for directly measuring piezoelectric ceramic modulators. Summary of the Invention

[0009] To address the current lack of dedicated technology for directly measuring piezoelectric ceramic modulators, this invention provides a measuring device for measuring piezoelectric ceramic modulators, comprising:

[0010] Narrow linewidth laser, first fiber coupler, second fiber coupler, optical oscilloscope, piezoelectric ceramic drive signal source, and fiber delay line;

[0011] The output end of the narrow linewidth laser is connected to the input end of the first fiber coupler; the narrow linewidth laser is used to generate stable laser light, which is then injected into the first fiber coupler as input light.

[0012] The output of the first fiber coupler is connected to the piezoelectric ceramic modulator under test and the fiber delay line, respectively; the optical signal output by the first fiber coupler is output to the piezoelectric ceramic modulator under test and the fiber delay line, respectively.

[0013] The output end of the piezoelectric ceramic modulator under test and the fiber delay line are connected to the input end of the second fiber coupler; the optical signal output by the piezoelectric ceramic modulator under test and the fiber delay line is injected into the second fiber coupler.

[0014] The output of the second fiber optic coupler is connected to the optical oscilloscope; the second fiber optic coupler outputs the optical signal to the optical oscilloscope.

[0015] The output terminal of the piezoelectric ceramic drive signal source is electrically connected to the control voltage input terminal of the piezoelectric ceramic modulator under test; the piezoelectric ceramic drive signal source outputs a drive electrical signal to the piezoelectric ceramic modulator under test.

[0016] Furthermore, the fiber delay line is a standard piezoelectric ceramic modulator of the same type.

[0017] Furthermore, it also includes: polarization controllers mounted on the two interference arms, wherein the polarization controllers are electric polarization controllers.

[0018] Furthermore, it also includes: polarization controllers mounted on each of the two interference arms, wherein the polarization controllers are manual polarization controllers. Furthermore, the piezoelectric ceramic driving signal source is a high-frequency sinusoidal signal source, the frequency of which is a resonant frequency of the piezoelectric ceramic, and the voltage amplitude output by the driving signal source is the maximum operating voltage of the piezoelectric ceramic.

[0019] Furthermore, the piezoelectric ceramic driving signal source is specifically a 220V AC voltage regulator.

[0020] Furthermore, the piezoelectric ceramic driving signal source outputs a driving signal to the piezoelectric ceramic modulator under test, modulates the envelope of the output signal of the piezoelectric ceramic modulator under test, and obtains the performance parameters of the piezoelectric ceramic modulator under test by processing the envelope signal.

[0021] Furthermore, an optical oscilloscope is used to display the optical signal waveform output by the second fiber optic coupler.

[0022] This invention also provides a measuring device for measuring piezoelectric ceramic modulators according to any one of the preceding claims, and a method for measuring piezoelectric ceramic modulators, characterized in that it includes:

[0023] Without applying any driving signal to the piezoelectric ceramic modulator under test, the maximum and minimum output power are obtained using an optical oscilloscope, and the power of the two interference arms is calculated.

[0024] Turn on the piezoelectric ceramic driver power supply, gradually increase the output voltage to modulate the envelope of the initial signal, and acquire the envelope signal through an optical oscilloscope;

[0025] The average value of the envelope modulation signal is calculated to obtain the operating point under the current conditions; using the operating point, the envelope curve corresponding to the envelope signal after eliminating the operating point drift is obtained;

[0026] Harmonic analysis is performed on the envelope curve, and the modulation characteristic curve of the piezoelectric ceramic modulator under test is determined based on the ratio of the second harmonic to the fourth harmonic in the analysis results.

[0027] Furthermore, the maximum and minimum output power are obtained using an optical oscilloscope, and the power of the two interferometer arms is calculated, including:

[0028] The optical oscilloscope achieves a maximum output power of P. maxThe minimum output power is P min ;

[0029] The powers P1 and P2 of the two interference arms are determined using the following formulas (1) and (2).

[0030]

[0031] Furthermore, the average value of the envelope signal is calculated to obtain the operating point under the current conditions, including:

[0032] The average value P is calculated for the envelope signal. ave Using formula (3), the working point θ0 under the current conditions is obtained.

[0033]

[0034] Furthermore, harmonic analysis is performed on the envelope curve, and the modulation characteristic curve of the piezoelectric ceramic is determined based on the ratio of the second harmonic to the fourth harmonic in the analysis results, including:

[0035] The envelope curve is given by formula (4). Harmonic analysis is performed on the envelope curve.

[0036]

[0037] In the formula, ω m It is the frequency of the driving signal source, θ m The modulation index and harmonic analysis results of the piezoelectric ceramic modulator under test are as follows: fundamental frequency P1(t):

[0038] P1(t)=P 1m sinω m t = P ave [-sinθ0J1(θ m )]sinω m t (5)

[0039] Second harmonic P2(t):

[0040] P2(t)=P 2m cos2ω m t = P ave [-cosθ0J2(θ m )]cos2ω m t (6)

[0041] Fourth harmonic P4(t):

[0042] P4(t)=P 4m cos4ω m t = P ave [cosθ0J4(θ m)]cos4ω m t (7)

[0043] By taking the ratio of the second harmonic amplitude to the fourth harmonic amplitude, we obtain...

[0044] Solve for θ using formula (8) m And by changing the amplitude V of the output voltage of the driving signal source, θ is obtained. m The curve showing the change with voltage is a modulation characteristic curve.

[0045] This invention provides a measuring device and method for measuring piezoelectric ceramic modulators, solving the problem of the lack of performance measurement for existing piezoelectric ceramic modulators. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of a measuring device for measuring a piezoelectric ceramic modulator according to an embodiment of the present invention; in the figure, 1. narrow linewidth laser; 2. first fiber coupler; 3. piezoelectric ceramic modulator under test; 4. fiber delay line; 5. second fiber coupler; 6. optical oscilloscope; 7. piezoelectric ceramic driving signal source;

[0047] Figure 2 This is a schematic diagram of the structure of Embodiment 2 of the present invention; in the figure, 1. Narrow linewidth laser; 2. First fiber coupler; 3. Piezoelectric ceramic modulator under test; 5. Second fiber coupler; 6. Optical oscilloscope; 7. Piezoelectric ceramic drive signal source; 8. Standard piezoelectric ceramic modulator; 9. DC voltage regulator;

[0048] Figure 3 This is a schematic diagram of the structure of Embodiment 3 of the present invention; in the figure: 1. Narrow linewidth laser; 2. First fiber coupler; 3. Piezoelectric ceramic modulator under test; 4. Fiber delay line; 5. Second fiber coupler; 6. Optical oscilloscope; 7. Piezoelectric ceramic driving signal source; 10. First polarization controller; 11. Second polarization controller;

[0049] Figure 4 This is a schematic diagram of a measurement method and process for measuring a piezoelectric ceramic modulator provided in an embodiment of the present invention. Detailed Implementation

[0050] Numerous specific details are set forth in the following description to provide a full understanding of the invention. However, the invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0051] Example 1

[0052] See Figure 1 The present invention provides a measuring device for measuring a piezoelectric ceramic modulator, comprising: a narrow linewidth laser, a first fiber coupler, a second fiber coupler, an optical oscilloscope, a piezoelectric ceramic driving signal source, and an optical fiber delay line;

[0053] The output end of the narrow linewidth laser is connected to the input end of the first fiber coupler; the narrow linewidth laser is used to generate stable laser light, which is then injected into the first fiber coupler as input light.

[0054] The output of the first fiber coupler is connected to the piezoelectric ceramic modulator under test and the fiber delay line, respectively; the optical signal output by the first fiber coupler is output to the piezoelectric ceramic modulator under test and the fiber delay line, respectively.

[0055] The output end of the piezoelectric ceramic modulator under test and the fiber delay line are connected to the input end of the second fiber coupler; the optical signal output by the piezoelectric ceramic modulator under test and the fiber delay line is injected into the second fiber coupler.

[0056] The output of the second fiber optic coupler is connected to the optical oscilloscope; the second fiber optic coupler outputs the optical signal to the optical oscilloscope.

[0057] The output terminal of the piezoelectric ceramic drive signal source is connected to the control voltage input terminal of the piezoelectric ceramic modulator under test; the piezoelectric ceramic drive signal source outputs a drive electrical signal to the piezoelectric ceramic modulator under test.

[0058] Furthermore, the fiber delay line is a standard piezoelectric ceramic modulator of the same type.

[0059] Furthermore, polarization controllers are mounted on each of the two interference arms; these polarization controllers are electrically driven polarization controllers.

[0060] Furthermore, polarization controllers are mounted on the two interference arms, and the polarization controllers are either manual or manual, including two types: three-ring structure and extrusion structure.

[0061] Furthermore, the piezoelectric ceramic driving signal source is a high-frequency sinusoidal signal source, the frequency of which is a resonant frequency of the piezoelectric ceramic, and the voltage amplitude output by the driving signal source is the maximum operating voltage of the piezoelectric ceramic.

[0062] Furthermore, the piezoelectric ceramic driving signal source is specifically a 220V AC voltage regulator.

[0063] Furthermore, the piezoelectric ceramic driving signal source outputs a driving signal to the piezoelectric ceramic modulator under test, modulates the envelope of the output signal of the piezoelectric ceramic modulator under test, and obtains the performance parameters of the piezoelectric ceramic modulator under test by processing the envelope signal.

[0064] Furthermore, an optical oscilloscope is used to display the waveform of the optical signal output from the second fiber optic coupler and to perform data processing.

[0065] Specifically, the laser emitted by the narrow-linewidth laser 1 is connected to the first fiber coupler 2 via an optical fiber, splitting the laser into two paths: one path connects to the piezoelectric ceramic modulator 3 under test, and then enters the second fiber coupler 5; the other path also connects to the second fiber coupler 5 via an optical fiber delay line 4. The two signals interfere in the second fiber coupler, and the resulting optical signal is connected to an optical oscilloscope 6. The working principle is as follows: the narrow-linewidth light source 1 generates a stable laser, which is injected into the first fiber coupler 2; the first fiber coupler 2 splits the input light into two paths: one path connects to the piezoelectric ceramic modulator 3 under test, and the other path connects to an optical fiber delay line 4 with a length approximately equal to that of the piezoelectric ceramic modulator. Both optical fibers are simultaneously injected into the second fiber coupler 5, and the output of the second fiber coupler 5 is connected to the optical oscilloscope. The optical oscilloscope acquires the relevant output signals and performs data processing.

[0066] Example 2

[0067] See Figure 2 The difference from Embodiment 1 is that the fiber delay line 4 described in Embodiment 1 is replaced by a standard piezoelectric ceramic modulator 8 of the same type, which is connected to a DC voltage regulator 9. With this modification, adjusting the voltage of the DC voltage regulator 9 will change the operating point of the Mach-Zehnder interferometer, thereby ensuring the measuring device operates at its optimal state.

[0068] Example 3

[0069] See Figure 3 The difference from the embodiment is that polarization controller 10 and polarization controller 11 are added to the two interferometer arms of the Mach-Zehnder interferometer, respectively. By adjusting the two polarization controllers, the polarization states of the two coherent lights are made consistent, thereby obtaining the best interference effect.

[0070] Example 4

[0071] Based on the same inventive concept, this invention also provides a method for measuring piezoelectric ceramic modulators, such as... Figure 4 As shown, it includes the following steps:

[0072] Step S101: Without applying any driving signal to the piezoelectric ceramic modulator under test, obtain the maximum and minimum output power using an optical oscilloscope, and calculate the power of the two interference arms.

[0073] Step S102: Turn on the piezoelectric ceramic driving power supply, gradually increase the output voltage, modulate the envelope of the initial signal, and acquire the envelope signal through an optical oscilloscope;

[0074] Step S103: Calculate the average value of the envelope signal and obtain the operating point under the current conditions; obtain the envelope curve corresponding to the envelope signal after eliminating the drift of the operating point through the operating point;

[0075] Step S104: Perform harmonic analysis on the envelope curve, and determine the modulation characteristic curve of the piezoelectric ceramic based on the ratio of the second harmonic to the fourth harmonic in the analysis results.

[0076] Furthermore, the maximum and minimum output power are obtained using an optical oscilloscope, and the power of the two interferometer arms is calculated, including:

[0077] The optical oscilloscope achieves a maximum output power of P. max The minimum output power is P min ;

[0078] The powers P1 and P2 of the two interference arms are determined using the following formulas (1) and (2).

[0079]

[0080] Furthermore, the average value of the envelope modulation signal is calculated to obtain the operating point under the current conditions, including:

[0081] The average value P is calculated for the envelope modulation signal. ave Using formula (3), the working point θ0 under the current conditions is obtained.

[0082]

[0083] Furthermore, harmonic analysis is performed on the envelope curve, and the modulation characteristic curve of the piezoelectric ceramic is determined based on the ratio of the second harmonic to the fourth harmonic in the analysis results, including:

[0084] The envelope curve is given by formula (4). Harmonic analysis is performed on the envelope curve.

[0085]

[0086] In the formula, ω m It is the frequency of the driving signal source, θ m The modulation index and harmonic analysis results of the piezoelectric ceramic modulator under test are as follows: fundamental frequency P1(t):

[0087] P1(t)=P 1m sinω m t = P ave [-sinθ0J1(θ m )]sinω m t (5)

[0088] Second harmonic P2(t):

[0089] P2(t)=P 2m cos2ω m t = P ave [-cosθ0J2(θ m )]cos2ω m t (6)

[0090] Fourth harmonic P4(t):

[0091] P4(t)=P 4m cos4ω m t = P ave [cosθ0J4(θ m )]cos4ω m t (7)

[0092] By taking the ratio of the second harmonic amplitude to the fourth harmonic amplitude, we obtain...

[0093] Solve for θ using formula (8) m And by changing the amplitude V of the output voltage of the driving signal source, θ is obtained. m The curve showing the change with voltage is a modulation characteristic curve.

[0094] Furthermore, the measurement method for the piezoelectric ceramic modulator based on the Mach-Zehnder interferometer also includes the following steps:

[0095] Adjust the DC voltage regulator to change the DC operating point θ0 so that θ0≈0, thus obtaining the maximum modulation depth.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

Claims

1. A measurement method for measuring piezoelectric ceramic modulators, characterized in that, A measuring device is provided, comprising: a narrow linewidth laser, a first fiber coupler, a second fiber coupler, an optical oscilloscope, a piezoelectric ceramic driving signal source, and a fiber delay line; The output end of the narrow linewidth laser is connected to the input end of the first fiber coupler; the narrow linewidth laser is used to generate stable laser light, which is then injected into the first fiber coupler as input light. The output of the first fiber coupler is connected to the piezoelectric ceramic modulator under test and the fiber delay line, respectively; the optical signal output by the first fiber coupler is output to the piezoelectric ceramic modulator under test and the fiber delay line, respectively. The output end of the piezoelectric ceramic modulator under test and the fiber delay line are connected to the input end of the second fiber coupler; the optical signal output by the piezoelectric ceramic modulator under test and the fiber delay line is injected into the second fiber coupler. The output of the second fiber optic coupler is connected to the optical oscilloscope; the second fiber optic coupler outputs the optical signal to the optical oscilloscope. The output terminal of the piezoelectric ceramic drive signal source is electrically connected to the control voltage input terminal of the piezoelectric ceramic modulator under test; the piezoelectric ceramic drive signal source outputs a drive electrical signal to the piezoelectric ceramic modulator under test; The measurement method includes the following steps: Without applying any driving signal to the piezoelectric ceramic modulator under test, the maximum and minimum output power are obtained using an optical oscilloscope, and the power of the two interference arms is calculated. Turn on the piezoelectric ceramic driver power supply, gradually increase the output voltage to modulate the envelope of the initial signal, and acquire the envelope signal through an optical oscilloscope; The average value of the envelope signal is calculated to obtain the operating point under the current conditions; using the operating point, the envelope curve corresponding to the envelope signal after eliminating the operating point drift is obtained; Harmonic analysis is performed on the envelope curve, and the modulation characteristic curve of the piezoelectric ceramic is determined based on the ratio of the second harmonic to the fourth harmonic in the analysis results. The maximum and minimum output power are obtained using an optical oscilloscope, and the power of the two interferometer arms is calculated, including: The optical oscilloscope achieves its maximum output power as follows: Minimum output power is ; The power of the two interference arms is calculated using the following formulas (1) and (2). and , （1） （2）； The average value of the envelope signal is calculated to obtain the operating point under the current conditions, including: Calculate the average value of the envelope signal. The operating point under the current conditions can be obtained using formula (3). , （3）； Harmonic analysis is performed on the envelope curve, and the modulation characteristic curve of the piezoelectric ceramic is determined based on the ratio of the second harmonic to the fourth harmonic in the analysis results, including: The envelope curve is given by formula (4). Harmonic analysis is then performed on the envelope curve. （4） In the formula, It is the frequency of the driving signal source. The modulation index of the piezoelectric ceramic modulator under test, and the results of harmonic analysis: fundamental frequency : （5） Second harmonic : （6） Fourth harmonic : （7） By taking the ratio of the second harmonic amplitude to the fourth harmonic amplitude, we obtain... (8) Solve from formula (8) And change the amplitude of the output voltage of the drive signal source. V ,get The curve showing the change with voltage is a modulation characteristic curve.

2. The measurement method according to claim 1, characterized in that, The fiber delay line is a standard piezoelectric ceramic modulator of the same type.

3. The measurement method according to claim 1, characterized in that, Also includes: A polarization controller is mounted on each of the two interference arms. The polarization controller is an electric polarization controller.

4. The measurement method according to claim 1, characterized in that, Also includes: A polarization controller is mounted on each of the two interference arms. The polarization controller is a manual polarization controller.

5. The measurement method according to claim 1, characterized in that, The piezoelectric ceramic driving signal source is a high-frequency sinusoidal signal source. Its frequency is a resonant frequency of the piezoelectric ceramic, and the voltage amplitude output by the driving signal source is the maximum operating voltage of the piezoelectric ceramic.

6. The measurement method according to claim 1, characterized in that, The piezoelectric ceramic drive signal source is specifically a 220V AC voltage regulator.

7. The measurement method according to claim 1, characterized in that, An optical oscilloscope is used to display the waveform of the optical signal output from the second fiber optic coupler.

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