CN109580038B - Temperature sensing demodulation device and demodulation method based on microwave photon filter - Google Patents
Temperature sensing demodulation device and demodulation method based on microwave photon filter Download PDFInfo
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Abstract
The invention discloses a temperature sensing demodulation device and a demodulation method based on a microwave photonic filter, wherein the microwave photonic filter comprises a multi-wavelength fiber laser and a dispersion fiber, and is used for forming laser and coupling and outputting the laser; the temperature sensing demodulation device comprises an electro-optical modulator, a microwave signal source, a photoelectric detector, an electric power meter and a temperature demodulator; the electro-optical modulator is used for modulating the coupling laser to output a modulated optical signal; the dispersion optical fiber is used for sampling time delay on the modulation optical signal to output a time delay optical signal; the photoelectric detector is used for recovering the time-delay optical signal to obtain an electric signal; the electric power meter is used for measuring the power of the electric signal; the temperature demodulator is used for scanning the microwave signal frequency, acquiring the corresponding microwave signal frequency according to the maximum power of the electric signal measured by the electric power meter and acquiring the temperature change information induced by the optical fiber sensor; therefore, the optical fiber temperature sensing and demodulation are realized through a simple structure, and meanwhile, the required cost is reduced.
Description
Technical Field
The invention relates to the technical field of optical fiber sensing demodulation, in particular to a temperature sensing demodulation device and a temperature sensing demodulation method based on a microwave photonic filter.
Background
The optical fiber sensor has the characteristics of small volume, light weight, easy realization of remote and distributed measurement, explosion prevention, electric insulation, electromagnetic interference resistance and the like, thereby being widely applied to the field of remote measurement of temperature, stress and refractive index.
In the prior art, the structure of a michelson optical fiber interferometer and a mach-zehnder optical fiber interferometer is mostly adopted to measure the wavelength change in an interference spectrum, and then the change information of the temperature is judged according to the wavelength change in the interference spectrum; however, these measurement methods require high performance of the optical filter, which leads to an increase in implementation cost, and the structure thereof is complicated, and thus it is difficult to be popularized in practical use.
Disclosure of Invention
The present invention is directed to solving, at least to some extent, one of the technical problems in the art described above. Therefore, an object of the present invention is to provide a temperature sensing demodulation apparatus based on a microwave photonic filter, which has a simple structure, is convenient for quantitative production, has a low manufacturing cost, and is beneficial to the popularization of optical fiber temperature sensing and demodulation technologies.
The second purpose of the invention is to provide a temperature sensing demodulation method based on a microwave photon filter.
In order to achieve the above object, a first embodiment of the present invention provides a temperature sensing demodulation apparatus based on a microwave photonic filter, the microwave photonic filter includes a multi-wavelength fiber laser and a dispersive fiber, the multi-wavelength fiber laser includes a fiber sensor and a fiber coupler, the multi-wavelength fiber laser senses a temperature signal through the fiber sensor to form a laser, and the laser is coupled and output by the optical fiber coupler, the temperature sensing demodulation device comprises an electro-optical modulator, a microwave signal source, a photoelectric detector, an electric power meter and a temperature demodulator, the optical input port of the electro-optical modulator is connected with the first output port of the optical fiber coupler, the electric drive port of the electro-optical modulator is connected with the microwave signal source, the optical output port of the electro-optical modulator is connected with the input end of the photoelectric detector through the dispersion optical fiber, and the output end of the photoelectric detector is connected with the input end of the electric power meter; the electro-optical modulator is used for modulating the coupling laser output by the optical fiber coupler according to the microwave signal emitted by the microwave signal source so as to output a modulated optical signal; the dispersion optical fiber is used for sampling and delaying the modulated optical signal to output a delayed optical signal; the photoelectric detector is used for recovering the time-delay optical signal to obtain an electric signal; the electric power meter is used for measuring the power of the electric signal; the temperature demodulator is used for scanning the frequency of the microwave signal emitted by the microwave signal source, acquiring the frequency of the corresponding microwave signal according to the maximum power of the electric signal measured by the electric power meter, and acquiring the temperature change information induced by the optical fiber sensor according to the frequency of the microwave signal corresponding to the maximum power.
According to the temperature sensing demodulation device based on the microwave photonic filter, the microwave photonic filter comprises a multi-wavelength fiber laser and a dispersion fiber, the multi-wavelength fiber laser comprises a fiber sensor and a fiber coupler, the multi-wavelength fiber laser senses a temperature signal through the fiber sensor to form laser, and the laser is coupled and output by the optical fiber coupler, the temperature sensing demodulation device comprises an electro-optical modulator, a microwave signal source, a photoelectric detector, an electric power meter and a temperature demodulator, the optical input port of the electro-optical modulator is connected with the first output port of the optical fiber coupler, the electric drive port of the electro-optical modulator is connected with the microwave signal source, the optical output port of the electro-optical modulator is connected with the input end of the photoelectric detector through the dispersion optical fiber, and the output end of the photoelectric detector is connected with the input end of the electric power meter; the electro-optical modulator is used for modulating the coupling laser output by the optical fiber coupler according to the microwave signal emitted by the microwave signal source so as to output a modulated optical signal; the dispersion optical fiber is used for sampling and delaying the modulated optical signal to output a delayed optical signal; the photoelectric detector is used for recovering the time-delay optical signal to obtain an electric signal; the electric power meter is used for measuring the power of the electric signal; the temperature demodulator is used for scanning the frequency of the microwave signal emitted by the microwave signal source, acquiring the frequency of the corresponding microwave signal according to the maximum power of the electric signal measured by the electric power meter, and acquiring temperature change information induced by the optical fiber sensor according to the frequency of the microwave signal corresponding to the maximum power; therefore, the electromagnetic interference resistant remote temperature measurement is realized, the bandwidth is large, the optical fiber temperature sensing and demodulation are realized through a simple structure, the quantitative production is suitable, and meanwhile, the cost required by the optical fiber temperature sensing and demodulation technology in the popularization process is greatly reduced.
In addition, the microwave photonic filter-based temperature sensing demodulation device proposed according to the above embodiment of the present invention may further have the following additional technical features:
optionally, the multi-wavelength fiber laser further includes an optical amplifier and an optical isolator, an input port of the optical amplifier is connected to an output port of the optical fiber sensor, an output port of the optical amplifier is connected to an input port of the optical isolator, an output port of the optical isolator is connected to an input port of the optical fiber coupler, a second output port of the optical fiber coupler is connected to an input port of the optical fiber sensor, wherein the laser light amplified by the optical amplifier passes through the optical isolator, the optical fiber coupler and the optical fiber sensor to form the laser light.
Optionally, the optical fiber sensor is an interference optical fiber sensor, the optical fiber coupler is a 90:10 optical fiber coupler, the first output port of the optical fiber coupler is a 10% output port, the second output port of the optical fiber coupler is a 90% output port, and the optical amplifier is a semiconductor optical amplifier.
Optionally, when the optical fiber sensor senses the temperature signal, based on an electro-optic effect, the temperature change sensed by the optical fiber sensor changes a refractive index of an optical fiber to cause a change in an optical path difference between two arms of the optical fiber sensor, so that a center frequency of a passband of the microwave photonic filter changes, wherein when the center frequency of the passband of the microwave photonic filter is equal to a frequency of the microwave signal emitted by the microwave signal source, a power of the electrical signal measured by the electrical power meter is maximum.
Optionally, the temperature demodulator obtains the temperature variation information sensed by the optical fiber sensor according to the following formula:
fc＝(ξΔTLs+nΔL)/(Dλ2)
wherein n is the effective refractive index of the optical fiber, xi is the thermo-optic coefficient of the optical fiber material, and LsFor sensing the length of the optical fiber, DeltaL is the length difference of two arms of the interference type optical fiber sensor, D is the time delay between unit wavelengths, lambda is the central wavelength, fcThe frequency of the microwave signal, Δ T, is the temperature variation.
In order to achieve the above object, a second embodiment of the present invention provides a temperature sensing demodulation method based on a microwave photonic filter, where the microwave photonic filter includes a multi-wavelength fiber laser and a dispersive fiber, the multi-wavelength fiber laser includes a fiber sensor and a fiber coupler, the multi-wavelength fiber laser senses a temperature signal through the fiber sensor to form laser, and couples and outputs the laser through the fiber coupler, and the temperature sensing demodulation method includes the following steps: modulating coupling laser output by the optical fiber coupler through an electro-optical modulator according to a microwave signal emitted by a microwave signal source to output a modulated optical signal; sampling and delaying the modulated optical signal through a dispersion optical fiber to output a delayed optical signal; recovering the time-delay optical signal through a photoelectric detector to obtain an electric signal, and measuring the power of the electric signal; and scanning the frequency of the microwave signal emitted by the microwave signal source, acquiring the corresponding frequency of the microwave signal according to the maximum power of the measured electric signal, and acquiring the temperature change information induced by the optical fiber sensor according to the frequency of the microwave signal corresponding to the maximum power.
According to the temperature sensing demodulation method based on the microwave photonic filter, the microwave photonic filter comprises a multi-wavelength fiber laser and a dispersion fiber, the multi-wavelength fiber laser comprises a fiber sensor and a fiber coupler, the multi-wavelength fiber laser senses a temperature signal through the fiber sensor to form laser, and the laser is coupled and output through the fiber coupler, and the temperature sensing demodulation method comprises the following steps: firstly, modulating coupling laser output by an optical fiber coupler through an electro-optical modulator according to a microwave signal emitted by a microwave signal source to output a modulated optical signal; then, sampling and delaying the modulated optical signal through a dispersion optical fiber to output a delayed optical signal; then, recovering the time delay optical signal through a photoelectric detector to obtain an electric signal, and measuring the power of the electric signal; then, scanning the frequency of the microwave signal emitted by the microwave signal source, acquiring the corresponding frequency of the microwave signal according to the maximum power of the measured electric signal, and acquiring temperature change information induced by the optical fiber sensor according to the frequency of the microwave signal corresponding to the maximum power; therefore, the electromagnetic interference resistant remote temperature measurement is realized, the bandwidth is large, the optical fiber temperature sensing and demodulation are realized through a simple structure, the quantitative production is suitable, and meanwhile, the cost required by the optical fiber temperature sensing and demodulation technology in the popularization process is greatly reduced.
In addition, the temperature sensing demodulation method based on the microwave photonic filter according to the above embodiment of the present invention may further have the following additional technical features:
optionally, the multi-wavelength fiber laser further includes an optical amplifier and an optical isolator, an input port of the optical amplifier is connected to an output port of the optical fiber sensor, an output port of the optical amplifier is connected to an input port of the optical isolator, an output port of the optical isolator is connected to an input port of the optical fiber coupler, a first output port of the optical fiber coupler is connected to an optical input port of the electro-optical modulator, a second output port of the optical fiber coupler is connected to an input port of the optical fiber sensor, and the laser light amplified by the optical amplifier passes through the optical isolator, the optical fiber coupler and the optical fiber sensor to form the laser light.
Optionally, the optical fiber sensor is an interference optical fiber sensor, the optical fiber coupler is a 90:10 optical fiber coupler, the first output port of the optical fiber coupler is a 10% output port, the second output port of the optical fiber coupler is a 90% output port, and the optical amplifier is a semiconductor optical amplifier.
Optionally, when the optical fiber sensor senses the temperature signal, based on an electro-optic effect, the temperature change sensed by the optical fiber sensor changes a refractive index of an optical fiber to cause a difference between optical path lengths of two arms of the optical fiber sensor to change, so that a center frequency of a passband of the microwave photonic filter changes, wherein when the center frequency of the passband of the microwave photonic filter is equal to a frequency of the microwave signal emitted by the microwave signal source, a power of the electrical signal measured by the electrical power meter is maximum.
Optionally, the temperature variation information sensed by the optical fiber sensor is obtained according to the following formula:
fc＝(ξΔTLs+nΔL)/(Dλ2)
wherein n is the effective refractive index of the optical fiber, xi is the thermo-optic coefficient of the optical fiber material, and LsFor sensing the length of the optical fiber, DeltaL is the length difference of two arms of the interference type optical fiber sensor, D is the time delay between unit wavelengths, lambda is the central wavelength, fcThe frequency of the microwave signal, Δ T, is the temperature variation.
Drawings
Fig. 1 is a schematic structural diagram of a temperature sensing demodulation apparatus based on a microwave photonic filter according to an embodiment of the present invention;
fig. 2 is a schematic flow chart of a microwave photonic filter-based temperature sensing demodulation method according to an embodiment of the present invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.
In the existing optical fiber temperature sensing demodulation technology, structures of a Michelson optical fiber interferometer and a Mach-Zehnder optical fiber interferometer are mostly adopted, and the structures are complex, high in implementation cost and not beneficial to popularization of the optical fiber temperature sensing and demodulation technology; according to the temperature sensing demodulation device based on the microwave photonic filter, the microwave photonic filter comprises a multi-wavelength fiber laser and a dispersion fiber, the multi-wavelength fiber laser comprises a fiber sensor and a fiber coupler, the multi-wavelength fiber laser senses a temperature signal through the fiber sensor to form laser, and the laser is coupled and output by the optical fiber coupler, the temperature sensing demodulation device comprises an electro-optical modulator, a microwave signal source, a photoelectric detector, an electric power meter and a temperature demodulator, the optical input port of the electro-optical modulator is connected with the first output port of the optical fiber coupler, the electric drive port of the electro-optical modulator is connected with the microwave signal source, the optical output port of the electro-optical modulator is connected with the input end of the photoelectric detector through the dispersion optical fiber, and the output end of the photoelectric detector is connected with the input end of the electric power meter; the electro-optical modulator is used for modulating the coupling laser output by the optical fiber coupler according to the microwave signal emitted by the microwave signal source so as to output a modulated optical signal; the dispersion optical fiber is used for sampling and delaying the modulated optical signal to output a delayed optical signal; the photoelectric detector is used for recovering the time-delay optical signal to obtain an electric signal; the electric power meter is used for measuring the power of the electric signal; the temperature demodulator is used for scanning the frequency of the microwave signal emitted by the microwave signal source, acquiring the frequency of the corresponding microwave signal according to the maximum power of the electric signal measured by the electric power meter, and acquiring temperature change information induced by the optical fiber sensor according to the frequency of the microwave signal corresponding to the maximum power; therefore, the electromagnetic interference resistant remote temperature measurement is realized, the bandwidth is large, the optical fiber temperature sensing and demodulation are realized through a simple structure, the quantitative production is suitable, and meanwhile, the cost required by the optical fiber temperature sensing and demodulation technology in the popularization process is greatly reduced.
In order to better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention can be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
In order to better understand the technical solution, the technical solution will be described in detail with reference to the drawings and the specific embodiments.
Fig. 1 is a schematic structural diagram of a temperature sensing demodulation apparatus based on a microwave photonic filter according to an embodiment of the present invention, and as shown in fig. 1, the temperature sensing demodulation apparatus based on a microwave photonic filter includes: a microwave photon filter 10 and a temperature sensing demodulation device 20.
The microwave photonic filter includes a multi-wavelength fiber laser 11 and a dispersion fiber 12, the multi-wavelength fiber laser 11 includes a fiber sensor 111 and a fiber coupler 112, the multi-wavelength fiber laser 11 senses a temperature signal through the fiber sensor 111 to form laser, and couples and outputs the laser through the fiber coupler 112.
That is, the multi-wavelength fiber laser 11 senses a temperature signal through the fiber sensor 111 to form laser light corresponding to the temperature signal, and couples out the formed laser light through the fiber coupler 112 to form coupled laser light.
In some embodiments, in the microwave photonic filter-based temperature sensing demodulation apparatus, the multi-wavelength fiber laser 11 further includes an optical amplifier 113 and an optical isolator 114, an input port of the optical amplifier 113 is connected to an output port of the optical fiber sensor 111, an output port of the optical amplifier 113 is connected to an input port of the optical isolator 114, an output port of the optical isolator 114 is connected to an input port of the optical fiber coupler 112, and a second output port of the optical fiber coupler 112 is connected to an input port of the optical fiber sensor 111, wherein the light amplified by the optical amplifier passes through the optical isolator 114, the optical fiber coupler 112, and the optical fiber sensor 111 to form laser light.
The type of the optical fiber sensor 111 may be various, and for example, the optical fiber sensor may be classified into an interference type and a non-interference type according to whether light interferes or not, and may be classified into an intensity modulation type, a polarization state modulation type, a phase modulation type, a frequency modulation type, and the like according to a modulation format of a measurement object.
As an example, the optical fiber sensor 111 is an interference type optical fiber sensor which senses a temperature signal to change a length difference between two arms of the interference type optical fiber sensor according to the sensed temperature signal, thereby generating laser light corresponding to the temperature signal; meanwhile, the interference type optical fiber sensor is also used as a wavelength selective device, namely, the wavelength of light is determined by the interference type optical fiber sensor; in the interference type optical fiber sensor, after the wavelength is selected, the laser light formed by the multi-wavelength optical fiber laser is a multi-wavelength laser light.
The coupling ratio of the fiber coupler 112 may be various.
As an example, the fiber coupler 112 is a 90: and 10 optical fiber couplers, wherein the first output port of the optical fiber coupler is a 10% output port, the second output port of the optical fiber coupler is a 90% output port, namely, the 10% output port is used for outputting the formed coupled laser, and the 90% output port is connected with the input port of the optical fiber sensor 111.
The optical amplifier 113 may be selected in various ways, for example, a raman optical amplifier.
As an example, the optical amplifier 113 is a semiconductor optical amplifier to amplify the light by the semiconductor optical amplifier and to reduce the influence of the backward light on the light source by an optical isolator subsequently, thereby maintaining the purity of the light source spectrum.
The temperature sensing demodulation device 20 comprises an electro-optical modulator 21, a microwave signal source 22, a photoelectric detector 23, an electric power meter 24 and a temperature demodulator (not shown in the figure).
The optical input port of the electro-optical modulator 21 is connected to the first output port of the optical fiber coupler 112, the electric drive port of the electro-optical modulator 21 is connected to the microwave signal source 22, the optical output port of the electro-optical modulator 21 is connected to the input end of the photodetector 23 through the dispersive optical fiber 12, and the output end of the photodetector 23 is connected to the input end of the electric power meter 24.
The electro-optical modulator 21 is configured to modulate the coupled laser output by the optical fiber coupler 112 according to the microwave signal emitted by the microwave signal source 22 to output a modulated optical signal.
The dispersive optical fiber 12 is used for sampling and delaying the modulated optical signal to output a delayed optical signal.
The photodetector 23 is used to recover the time-delayed optical signal to obtain an electrical signal.
The wattmeter 24 is used for measuring the power of the electrical signal, and the temperature demodulator is used for scanning the frequency of the microwave signal emitted by the microwave signal source 22, obtaining the corresponding frequency of the microwave signal according to the maximum power of the electrical signal measured by the wattmeter 24, and obtaining the temperature variation information sensed by the optical fiber sensor 111 according to the frequency of the microwave signal corresponding to the maximum power.
That is, the first output port of the optical fiber coupler 112 is connected to the optical input port of the electro-optical modulator 21 to output the formed coupled laser light to the electro-optical modulator 21, the electrical driving port of the electro-optical modulator 21 is connected to the microwave signal source 22 to modulate the coupled laser light according to the microwave signal emitted from the microwave signal source 22 through the electro-optical modulator 21, the optical output port of the electro-optical modulator 21 is connected to one end of the dispersion fiber 12 to input the modulated optical signal after modulation of the coupled laser light to the dispersion fiber 12, the other end of the dispersion fiber 12 is connected to the input end of the photodetector 23 to input the time-delayed optical signal after sampling and time delay of the dispersion fiber 12 to the photodetector 23, the photodetector 23 recovers the time-delayed optical signal into an electrical signal after receiving the time-delayed optical signal and measures the power of the electrical signal through the electrical power meter 24, and when the measured power is the maximum power, obtaining the current microwave signal frequency corresponding to the maximum power through the temperature demodulator, and calculating to obtain the temperature change information sensed by the optical fiber sensor 111 according to the current microwave signal frequency corresponding to the maximum power.
It should be noted that, in the process of sensing the temperature signal by the optical fiber sensor 111, based on the photoelectric effect, when the temperature changes, the refractive index of the optical fiber changes, so that the optical path difference between the two arms of the optical fiber sensor 111 changes, and the center frequency of the passband of the microwave photonic filter 10 changes, wherein when the center frequency of the passband of the microwave photonic filter 10 is equal to the frequency of the microwave signal source 22, the power of the electrical signal measured by the electrical power meter 24 is the maximum; therefore, when the power of the electrical signal measured by the electrical power meter 24 is the maximum power, the frequency of the microwave signal emitted by the microwave signal source can be scanned by the temperature demodulator, so as to obtain the temperature change information according to the scanned frequency of the microwave signal.
As an example, the temperature demodulator obtains the temperature variation information sensed by the optical fiber sensor according to the following formula:
fc＝(ξΔTLs+nΔL)/(Dλ2)
wherein n is the effective refractive index of the optical fiber, xi is the thermo-optic coefficient of the optical fiber material, and LsFor sensing the length of the optical fiber, DeltaL is the length difference of two arms of the interference type optical fiber sensor, D is the time delay between unit wavelengths, lambda is the central wavelength, fcThe frequency of the microwave signal, Δ T, is the temperature variation.
In summary, according to the temperature sensing demodulation apparatus based on the microwave photonic filter of the embodiment of the present invention, the microwave photonic filter includes a multi-wavelength fiber laser and a dispersive fiber, the multi-wavelength fiber laser includes a fiber sensor and a fiber coupler, the multi-wavelength fiber laser senses a temperature signal through the fiber sensor to form a laser, and the laser is coupled and output by the optical fiber coupler, the temperature sensing demodulation device comprises an electro-optical modulator, a microwave signal source, a photoelectric detector, an electric power meter and a temperature demodulator, the optical input port of the electro-optical modulator is connected with the first output port of the optical fiber coupler, the electric drive port of the electro-optical modulator is connected with the microwave signal source, the optical output port of the electro-optical modulator is connected with the input end of the photoelectric detector through the dispersion optical fiber, and the output end of the photoelectric detector is connected with the input end of the electric power meter; the electro-optical modulator is used for modulating the coupling laser output by the optical fiber coupler according to the microwave signal emitted by the microwave signal source so as to output a modulated optical signal; the dispersion optical fiber is used for sampling and delaying the modulated optical signal to output a delayed optical signal; the photoelectric detector is used for recovering the time-delay optical signal to obtain an electric signal; the electric power meter is used for measuring the power of the electric signal; the temperature demodulator is used for scanning the frequency of the microwave signal emitted by the microwave signal source, acquiring the frequency of the corresponding microwave signal according to the maximum power of the electric signal measured by the electric power meter, and acquiring temperature change information induced by the optical fiber sensor according to the frequency of the microwave signal corresponding to the maximum power; therefore, the electromagnetic interference resistant remote temperature measurement is realized, the bandwidth is large, the optical fiber temperature sensing and demodulation are realized through a simple structure, the quantitative production is suitable, and meanwhile, the cost required by the optical fiber temperature sensing and demodulation technology in the popularization process is greatly reduced.
In order to implement the foregoing embodiment, as shown in fig. 2, an embodiment of the present invention further provides a temperature sensing demodulation method based on a microwave photonic filter, where the microwave photonic filter includes a multi-wavelength fiber laser and a dispersive fiber, the multi-wavelength fiber laser includes a fiber sensor and a fiber coupler, the multi-wavelength fiber laser senses a temperature signal through the fiber sensor to form laser, and couples and outputs the laser through the fiber coupler, and the temperature sensing demodulation method includes the following steps:
s101, modulating coupling laser output by an optical fiber coupler through an electro-optical modulator according to a microwave signal emitted by a microwave signal source to output a modulated optical signal;
that is, the microwave signal source emits a microwave signal, so that the electro-optical modulator modulates the received coupled laser according to the microwave signal emitted by the microwave signal source, and outputs a modulated optical signal from the optical output port of the electro-optical modulator after modulation. The coupled laser light emitted from the multi-wavelength fiber laser is a multi-wavelength laser light.
S102, sampling and delaying the modulated optical signal through a dispersion optical fiber to output a delayed optical signal;
s103, recovering the time delay optical signal through a photoelectric detector to obtain an electric signal, and measuring the power of the electric signal;
that is, the optical output port of the electro-optical modulator is connected to one end of the dispersion fiber to sample and delay the output modulated optical signal through the dispersion fiber, and meanwhile, the other end of the dispersion fiber is connected to the photodetector, and the photodetector recovers the delayed optical signal sampled and delayed by the dispersion fiber to form a corresponding electrical signal, and then measures the power of the recovered electrical signal.
S104, scanning the frequency of the microwave signal emitted by the microwave signal source, acquiring the corresponding frequency of the microwave signal according to the maximum power of the measured electric signal, and acquiring the temperature change information induced by the optical fiber sensor according to the frequency of the microwave signal corresponding to the maximum power.
That is, the frequency of the microwave signal emitted by the microwave signal source is scanned, and when the power of the measured electrical signal is the maximum power, the frequency of the microwave signal corresponding to the maximum power is obtained, and the temperature change information sensed by the optical fiber sensor is obtained according to the frequency of the microwave signal corresponding to the maximum power.
As an example, the electric signal recovered by the photodetector is measured by an electric power meter, when the power measured by the electric power meter is the maximum power, the microwave signal frequency corresponding to the maximum power is obtained by the temperature demodulator, and the temperature change information is obtained according to the corresponding relationship between the microwave signal frequency and the temperature change amount.
It should be noted that, when the external temperature to be measured acts on the interference type optical fiber sensor, due to the electro-optic effect, the change of the temperature may cause the change of the refractive index of the optical fiber, thereby causing the change of the optical path difference between the two arms of the interference type optical fiber sensor, and further causing the change of the center frequency of the passband of the microwave photonic filter, wherein, when the center frequency of the microwave photonic filter is equal to the microwave signal frequency of the microwave signal emitted by the microwave signal source, the power measured by the photodetector is the maximum power.
As another example, when measuring with the first pass band of a microwave photonic filter, the relationship between its center frequency fc and the measured temperature change Δ T is,
fc＝(ξΔTLs+nΔL)/(Dλ2)
wherein n is the effective refractive index of the optical fiber, xi is the thermo-optic coefficient of the optical fiber material, and LsFor sensing the length of the optical fiber, DeltaL is the length difference of two arms of the interference type optical fiber sensor, D is the time delay between unit wavelengths, lambda is the central wavelength, fcThe frequency of the microwave signal, Δ T, is the temperature variation.
It should be noted that the above description about the microwave photonic filter-based temperature sensing demodulation apparatus in fig. 1 is also applicable to the microwave photonic filter-based temperature sensing demodulation method, and is not repeated herein.
In summary, according to the temperature sensing demodulation method based on the microwave photonic filter in the embodiment of the present invention, the microwave photonic filter includes a multi-wavelength fiber laser and a dispersive fiber, the multi-wavelength fiber laser includes a fiber sensor and a fiber coupler, the multi-wavelength fiber laser senses a temperature signal through the fiber sensor to form laser, and couples and outputs the laser through the fiber coupler, and the temperature sensing demodulation method includes the following steps: firstly, modulating coupling laser output by an optical fiber coupler through an electro-optical modulator according to a microwave signal emitted by a microwave signal source to output a modulated optical signal; then, sampling and delaying the modulated optical signal through a dispersion optical fiber to output a delayed optical signal; then, recovering the time delay optical signal through a photoelectric detector to obtain an electric signal, and measuring the power of the electric signal; then, scanning the frequency of the microwave signal emitted by the microwave signal source, acquiring the corresponding frequency of the microwave signal according to the maximum power of the measured electric signal, and acquiring temperature change information induced by the optical fiber sensor according to the frequency of the microwave signal corresponding to the maximum power; therefore, the electromagnetic interference resistant remote temperature measurement is realized, the bandwidth is large, the optical fiber temperature sensing and demodulation are realized through a simple structure, the quantitative production is suitable, and meanwhile, the cost required by the optical fiber temperature sensing and demodulation technology in the popularization process is greatly reduced.
As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
It should be noted that in the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by one and the same item of hardware. The usage of the words first, second and third, etcetera do not indicate any ordering. These words may be interpreted as names.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
In the description of the present invention, it is to be understood that the terms "first", "second" and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.
In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above should not be understood to necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
Claims (8)
1. A temperature sensing demodulation device based on a microwave photon filter is characterized in that the microwave photon filter comprises a multi-wavelength fiber laser and a dispersion fiber, the multi-wavelength fiber laser comprises a fiber sensor and a fiber coupler, the multi-wavelength fiber laser senses a temperature signal through the fiber sensor to form laser, and couples and outputs the laser through the fiber coupler, the temperature sensing demodulation device comprises an electro-optical modulator, a microwave signal source, a photoelectric detector, an electric power meter and a temperature demodulator, wherein,
an optical input port of the electro-optical modulator is connected with a first output port of the optical fiber coupler, an electric drive port of the electro-optical modulator is connected with the microwave signal source, an optical output port of the electro-optical modulator is connected with an input end of the photoelectric detector through the dispersion optical fiber, and an output end of the photoelectric detector is connected with an input end of the electric power meter;
the electro-optical modulator is used for modulating the coupling laser output by the optical fiber coupler according to the microwave signal emitted by the microwave signal source so as to output a modulated optical signal;
the dispersion optical fiber is used for sampling and delaying the modulated optical signal to output a delayed optical signal;
the photoelectric detector is used for recovering the time-delay optical signal to obtain an electric signal;
the electric power meter is used for measuring the power of the electric signal;
the temperature demodulator is used for scanning the frequency of the microwave signal emitted by the microwave signal source, acquiring the frequency of the corresponding microwave signal according to the maximum power of the electric signal measured by the electric power meter, and acquiring temperature change information induced by the optical fiber sensor according to the frequency of the microwave signal corresponding to the maximum power;
the multi-wavelength fiber laser further comprises an optical amplifier and an optical isolator, an input port of the optical amplifier is connected with an output port of the optical fiber sensor, an output port of the optical amplifier is connected with an input port of the optical isolator, an output port of the optical isolator is connected with an input port of the optical fiber coupler, a second output port of the optical fiber coupler is connected with an input port of the optical fiber sensor, and the laser is formed by amplified light passing through the optical amplifier, the optical fiber coupler and the optical fiber sensor.
2. The microwave photonic filter-based temperature sensing demodulation apparatus according to claim 1, wherein the optical fiber sensor is an interferometric optical fiber sensor, the optical fiber coupler is a 90:10 optical fiber coupler, the first output port of the optical fiber coupler is a 10% output port, the second output port of the optical fiber coupler is a 90% output port, and the optical amplifier is a semiconductor optical amplifier.
3. The microwave photonic filter based temperature sensing demodulation apparatus according to any one of claims 1-2, wherein when the optical fiber sensor senses the temperature signal, the temperature variation sensed by the optical fiber sensor causes the refractive index of the optical fiber to vary based on the electro-optical effect, so as to cause the optical path difference between the two arms of the optical fiber sensor to vary, so that the center frequency of the passband of the microwave photonic filter varies,
when the passband center frequency of the microwave photonic filter is equal to the frequency of the microwave signal emitted by the microwave signal source, the power of the electrical signal measured by the electrical power meter is maximum.
4. The microwave photonic filter based temperature sensing demodulation apparatus according to claim 3, wherein the temperature demodulator obtains the temperature variation information sensed by the optical fiber sensor according to the following formula:
fc＝(ξΔTLs+nΔL)/(Dλ2)
wherein n is the effective refractive index of the optical fiber, xi is the thermo-optic coefficient of the optical fiber material, and LsFor sensing the length of the optical fiber, DeltaL is the length difference of two arms of the interference type optical fiber sensor, D is the time delay between unit wavelengths, lambda is the central wavelength, fcThe frequency of the microwave signal, Δ T, is the temperature variation.
5. A temperature sensing demodulation method based on a microwave photonic filter is characterized in that the microwave photonic filter comprises a multi-wavelength fiber laser and a dispersion fiber, the multi-wavelength fiber laser comprises a fiber sensor and a fiber coupler, the multi-wavelength fiber laser senses a temperature signal through the fiber sensor to form laser, and the laser is coupled and output through the fiber coupler, and the temperature sensing demodulation method comprises the following steps:
modulating the coupled laser output by the optical fiber coupler through an electro-optical modulator according to a microwave signal emitted by a microwave signal source to output a modulated optical signal;
sampling and delaying the modulated optical signal through a dispersion optical fiber to output a delayed optical signal;
recovering the time-delay optical signal through a photoelectric detector to obtain an electric signal, and measuring the power of the electric signal;
scanning the frequency of a microwave signal emitted by the microwave signal source, acquiring the frequency of a corresponding microwave signal according to the measured maximum power of the electric signal, and acquiring temperature change information induced by the optical fiber sensor according to the frequency of the microwave signal corresponding to the maximum power;
the multi-wavelength fiber laser also comprises an optical amplifier and an optical isolator, wherein the input port of the optical amplifier is connected with the output port of the optical fiber sensor, the output port of the optical amplifier is connected with the input port of the optical isolator, the output port of the optical isolator is connected with the input port of the optical fiber coupler, the first output port of the optical fiber coupler is connected with the optical input port of the electro-optical modulator, the second output port of the optical fiber coupler is connected with the input port of the optical fiber sensor, wherein,
the light amplified by the optical amplifier passes through the optical isolator, the optical fiber coupler, and the optical fiber sensor to form the laser.
6. The microwave photonic filter-based temperature sensing demodulation method according to claim 5, wherein the optical fiber sensor is an interferometric optical fiber sensor, the optical fiber coupler is a 90:10 optical fiber coupler, the first output port of the optical fiber coupler is a 10% output port, the second output port of the optical fiber coupler is a 90% output port, and the optical amplifier is a semiconductor optical amplifier.
7. The microwave photonic filter-based temperature sensing demodulation method according to any one of claims 5 to 6, wherein when the optical fiber sensor senses the temperature signal, the temperature change sensed by the optical fiber sensor causes the refractive index of the optical fiber to change based on the electro-optical effect, so as to cause the optical path difference between the two arms of the optical fiber sensor to change, so that the center frequency of the passband of the microwave photonic filter changes,
when the passband center frequency of the microwave photonic filter is equal to the frequency of the microwave signal emitted by the microwave signal source, the power of the electrical signal measured by the electrical power meter is maximum.
8. The microwave photonic filter-based temperature sensing demodulation method according to claim 7, wherein the temperature variation information sensed by the optical fiber sensor is obtained according to the following formula:
fc＝(ξΔTLs+nΔL)/(Dλ2)
wherein n is the effective refractive index of the optical fiber, ξ is the thermo-optic coefficient of the optical fiber material, Ls is the length of the sensing optical fiber, Δ L is the length difference of two arms of the interference type optical fiber sensor, D is the time delay between unit wavelengths, λ is the center wavelength, fc is the frequency of the microwave signal, and Δ T is the temperature variation.
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