139 results about "Microwave photonic filter" patented technology

The invention discloses a broadband tunable single-passband microwave photon filter generating system. The system comprises a laser, an optical coupler, a polarization modulator, a dispersion displacement optical fiber, a photoelectric detector, a vector network analyzer, a strength modulator and an optical fiber; the laser is used for providing continuous light signals; the optical coupler is used for dividing the continuous light signals into the first path of light signals and the second path of light signals; the polarization modulator is used for modulating the polarization state of the first path of light signals; the dispersion displacement light fiber is used for performing stimulated Brillouin scattering on the detection light signals under the induction effect of pump light signals; the photoelectric detector is used for receiving the detection light signals which are processed in a stimulated Brillouin scattering mode and output by the dispersion displacement optical fiber and generating microwave signals; the vector network analyzer is used for receiving microwave signals output by the photoelectric detector, performing measurement frequency response on the microwave signals, and outputting the microwave signals to the a first polarization modulator at the same time; the strength modulator is used for modulating the polarization state of the first path of light signals and outputting the first path of light signals which are modulated; the optical fiber is used for filtering the first path of light signals which are modulated, and the first path of light signals serve as the pump light signals.

The invention discloses a high bandwidth tunable double-passband microwave photon filter, belongs to the field of microwave photonics, and relates to the high bandwidth tunable double-passband microwave photon filter based on high non-linear optical fiber excited brillouin scattering effects and multiple pumping signals. The filter consists of a first laser, a first phase modulator, an opto-isolator, a vector network analyzer, a high non-linear optical fiber, a second laser, a strength modulator, a microwave signal source, a second phase regulator, a pulse code generator, an erbium-doped optical fiber amplifier, an optical circulator and a photoelectric detector. The filter is based on phase modulation and excited brillouin scattering effects caused by two pumping signals, and thus double-passband output of the microwave photon filter is achieved. By changing the frequency of the two pumping signals, the frequency of two passband centers can be randomly modulated within a certain frequency range. Through binary phase shift keying modulation on the pumping signals, the bandwidth of the pumping signals can be changed, and thus adjustment on the output bandwidth of the filter is achieved.

A tunable-frequency photoelectric oscillation device based on a wide spectrum light source comprises the wide spectrum light source, an optical filter, a first light amplifier, a second light amplifier, a first optical fiber coupler, a second optical fiber coupler, a third optical fiber coupler, a first polarization controller, a second polarization controller, a dimming-adjustable delay line, an photoelectric modulator, a color-dispersion optical fiber, a first photoelectric detector, a second photoelectric detector, a microwave amplifier, a first optical fiber patch cord, a second optical fiber patch cord, a third optical fiber patch cord, a fourth optical fiber patch cord, a fifth optical fiber patch cord, a sixth optical fiber patch cord, a seventh optical fiber patch cord, a first cable and a second cable. The tunable-frequency photoelectric oscillation device based on the wide spectrum light source can generate wideband-adjustable microwave signals, adopts a microwave photon filter to replace a traditional point filter, overcomes the defect that a traditional photoelectric oscillator based on wide spectrum source cutting can not generate signals at certain frequency points, and has the advantages of being low in cost, adjustable in wideband, and low in phase noise.

The invention discloses a single-response microwave photonic filter-based frequency measurement device and a measurement method, and relates to a frequency measurement device and method. The frequency measurement device is provided with a broadband light source, a Mach-Zehnder fiber optic interferometer, an electro-optical modulator, an optical fiber amplifier, a microwave antenna, a dispersion optical fiber, a photo detector and an electrodynamic meter. A tunable single-response microwave photonic filter can be realized by using a structure based on combined Mach-Zehnder fiber optic interferometer spectral division and dispersion optical fiber; the transmission peak frequency position of the single-response microwave photonic filter is adjusted by scanning an adjustable delay line of the optical fiber; and the detection of the frequency of a measured microwave signal is realized by restoring measurement of electric signal power through the photo detector. The microwave electronic filter has an incoherent filter structure; and meanwhile, the detection of a multi-frequency microwave signal is realized through quick length scanning of the adjustable delay line. Remote high-frequency microwave signal frequency measurement of electromagnetic interference can be realized.

The invention provides a cascaded microwave photonic filter-based photoelectric oscillator with a tunable broadband. The cascaded microwave photonic filter-based photoelectric oscillator comprises a first laser, a first polarization controller, a phase modulator, a first MPBF unit, a second MPBF unit, a first variable optical attenuator, a photodiode, an electric amplifier and an electric power divider which are sequentially connected, wherein a first output end of the electric power divider is used for outputting a generated microwave signal; a second output end of the electric power divideris connected with a radio frequency port of the phase modulator; when the photoelectric oscillator works, a phase modulation signal enters the first MPBF unit and then first mode selection is carriedout by using a single bandpass microwave photonic filter with the tunable broadband, thereby selecting an oscillation starting frequency of the OEO, and the phase modulation signal passes through thesecond MPBF unit and then auxiliary mode selection through an ultra-narrow bandwidth MPBF is achieved, thereby achieving single-mode oscillation starting of the OEO. A cascaded microwave photonic bandpass filter is utilized and combined with the OEO, so that single-mode oscillation starting of the OEO is achieved through multiple mode selection; and the broadband tenability of the OEO can be achieved through adjusting the central wavelength of the first MPBF unit.

The invention discloses a microwave photon filter of a multi-wavelength light source and a tuning and reconfiguring method of the microwave photon filter. The microwave photon filter of the multi-wavelength light source comprises a multi-wavelength light source generator and a microwave filter device. The microwave filter device comprises a phase modulator, an adjustable dispersion compensator, a first erbium-doped optical fiber amplifier, a photoelectric detector and a vector network analyzer. A comb-shaped optical fiber of the multi-wavelength light source generator is a programmable optical filter. By observing response curve of the network analyzer, dispersion value of the adjustable dispersion compensator is adjusted, time delay between adjacent optical wavelengths of adjacent multi-wavelength light is changed continuously, and central continuous tuning of the microwave photon filter can be realized. The number of comb-shaped pass bands is set by the programmable optical filter to change the number of emitting wavelengths, and adjustment of the bandwidth of the microwave photon filter is realized. Tunable capacity and reconfigurability of the microwave photon filter are realized, and the microwave photon filter can be more flexibly used for the microwave signal processing system.

The invention discloses a temperature measurement device based on a single-passband microwave photon filter. According to the temperature measurement device, the structure of combining spectrum segmentation of a Mach-Zehnder optical fiber interferometer and a chromatic dispersion optical fiber is adopted, and the single-passband microwave photon filter is achieved. One arm of the Mach-Zehnder optical fiber interferometer is connected with a sensing optical fiber, and the other arm of the Mach-Zehnder optical fiber interferometer is connected with a reference optical fiber. The optical path difference of the two arms of the Mach-Zehnder optical fiber interferometer is changed by temperature signals acting on the sensing optical fiber, and then the passband central frequency of the single-passband microwave photon filter is changed. Modulation microwave signal frequency is scanned, and the measured temperature is measured by obtaining the passband center frequency by measuring the recovery electric signal power through a photoelectric detector. The invention further discloses a temperature measurement method based on the single-passband microwave photon filter. By means of the temperature measurement device and device, remote temperature measurement preventive to electromagnetic interference can be achieved, and the cost and complexity of temperature measurement are greatly lowered.

The invention discloses a non-local-oscillator low-phase-noise microwave signal optical frequency-doubling generation device and method, and belongs to the technical field of microwave signal generation. According to the device and the method, a narrow-band microwave photonic filter is formed by utilizing an equivalent phase modulation characteristic of one double parallel Mach-Zehnder modulator (DP-MZM) integrated in a polarized multiplexed double parallel Mach-Zehnder modulator (DP-QPSK modulator) and a phase shifting fiber bragg grating (PS-FBG); and in an optoelectronic oscillator, generation of a frequency tunable low-phase-noise microwave resonance signal is implemented. Signal frequency doubling of the generated microwave resonance signal is implemented by the other DP-MZM integrated in the DP-QPSK modulator so as to generate a high-frequency microwave signal. The non-local-oscillator low-phase-noise microwave signal optical frequency-doubling generation device and method disclosed by the invention can overcome the defect of limitation of the electronic bottleneck of an electronic system in the aspect of generating the high-frequency low-phase-noise microwave signal, and implement generation of the low-phase-noise microwave signal with a magnitude of dozens of GHz and even hundreds of GHz.

The invention discloses a tunable single-passband microwave photonic filter based on Brillouin optical carrier recovery. The tunable single-passband microwave photonic filter comprises a tunable laser, an optical coupler, a first optical amplifier, a second optical amplifier, a first optical circulator, a second optical circulator, first-section single-mode optical fibers, second-section single-mode optical fibers, a first optical polarization controller, a second optical polarization controller, a Mach-Zehnder modulator, an optical fiber Fabry-Perot filer, an optical isolator, a high-speed photoelectric detector and an electric vector network analyzer, wherein the first-section single-mode optical fibers and the second-section single-mode optical fibers are each wound together in a compound mode. By means of the tunable single-passband microwave photonic filter based on the Brillouin optical carrier recovery, the microwave photonic filter with single-passband frequency responses can be achieved, the wavelength of outgoing light of the tunable laser can be changed, and the broadband of the filtering passband of the microwave photonic filter can be tunable.

The invention discloses a microwave photon filter based on a multi-wavelength fiber laser and chirp Bragg gratings, belongs to the field of microwave photon filters and particularly relates to a microwave photon filter for free spectral range multiplying. In the fiber laser, a Sagnac ring optical filter composed of a polarization maintaining optical fiber, a polarization controller and a coupler has a wavelength selection function and an apodizing function, and stable multi-wavelength output with the basically-same power is obtained by selecting a proper frequency stabilizing device. A fiber Bragg grating array serves as a time delay unit, the reflection wavelengths of the gratings correspond to the output wavelengths of a multi-wavelength laser respectively, the center distances between the adjacent gratings are the same, and thus the time delay differences generated between taps are the same. The chirp Bragg gratings are introduced so that the time delay differences between the taps are reduced, under the condition that the suppression ratio of a main lobe and a side lobe is kept unchanged, the radio frequency response for free spectral range multiplying is obtained, and the free spectral range is greatly enlarged.

The invention provides a microwave photonic filter free of spurious interference based on an optical frequency comb. The microwave photonic filter free of the spurious interference based on the optical frequency comb comprises an optical frequency comb source, a quadratic-form phase processing unit, a modulator, a dispersive medium and a photoelectric detector, wherein the optical frequency comb source is used for carrying radio frequency signals to be filtered, each carrier wave component corresponds to a tap in a transverse filter structure, the quadratic-form phase processing unit is used for adjusting the whole optical phase of the optical frequency comb source too be a quadratic form, the modulator is used for modulating the radio frequency signals to be filtered to each carrier wave component of the optical frequency comb source, the dispersive medium is used for introducing equal delay among all carrier wave of the optical frequency comb source and enabling each carrier wave in the optical frequency comb source to be regarded as one tap in the transverse filter structure, and the photoelectric detector is used for converting optical signals into electric signals and outputting the filtered radio frequency signals. The microwave photonic filter free of spurious interference based on the optical frequency comb can effectively suppress the spurious frequency and does not affect the characteristic that the filter transmits the function. Passband tuning can not be limited by the traditional Nyquist area. In addition, the microwave photonic filter free of spurious interference based on the optical frequency comb has the advantages of being simple in structure and wide in application range.

The invention discloses a wide passband reconfigurable microwave quantum photon filtering device and filtering method based on stimulated brillouin scattering, relates to a microwave quantum photon filter based on the stimulated Brillouin scattering in optical fibers, and belongs to the optics and microwave crossing field. The wide passband reconfigurable microwave quantum photon filtering device and filtering method solves the problem that a passband of an existing microwave quantum photon filter is narrow. According to the quantum photon filtering device and filtering method, two lasers are adopted to respectively generate pump light and carrier wave light, two phase modulators are adopted to respectively conduct phase modulation on the pump light and the carrier wave light, two isolators are adopted to protect the lasers, the stimulated brillouin scattering occurs when first order lower edge frequency or first order upper edge frequency signals of the carrier wave in the optical fiber enter a stimulated Brillouin gain spectrum corresponding to the pump light, the width value of the edge frequency signals is amplified, a beat frequency signal is output through a detector, and then filtering of passband microwaves is realized. The quantum photon filtering device and filtering method is applied to microwave quantum photon filtering.

The invention relates to a double chirped Fourier domain mode-locked photoelectric oscillator and an application thereof and a communication system, which relate to the technical field of microwave photonics. The double chirped Fourier domain mode-locked photoelectric oscillator comprises two lasers, an optical coupler, a modulator, an optical filter, an optical delay line, a photoelectric detector, a power divider and an electric amplifier. The two lasers, the modulator, the optical fiber and the photoelectric detector constitute a double-pass-band sweep-frequency microwave photonic filter, of which the sweep frequency is realized by the sweep frequency of the two lasers or is realized by the sweep frequency of the optical filter. The double chirped Fourier domain mode-locked photoelectric oscillator provided by the invention does not need a high-speed electronic device. The output signals can be tuned. Broadband fast chirped microwave signals can be output.

The invention provides an underwater acoustic detection device based on a photoelectric oscillator. The device comprises a laser light source circuit, a photoelectric oscillation loop and a frequencydemodulation circuit. The device enables a phase-shifted fiber grating or a fiber grating F-P cavity interferometer to be embedded into a microwave photon filter, and uses an elastic cylinder to convert external acoustic wave changes into fiber grating stress or pressure changes, thereby enabling wavelength changes to be converted into the changes in the center frequency of the microwave photon filter, and enabling the frequency of the output microwave signal of the photoelectric oscillator to change. The underwater sound field detection is completed by analyzing the frequency changes by the digital signal demodulation technology. Compared to a conventional fiber optic hydrophone device, the device provided by the invention has higher accuracy, demodulation speed and signal to noise ratio,and a large dynamic range. The technical contents involved mainly include the microwave photon filter making technology, the multi-frequency photoelectric oscillation technology, the scalar sound pressure and three-dimensional sound field measurement technology, the signal demodulation technology, the packaging technology and the array multiplexing technology.

The invention discloses a tunable microwave photon band pass filter based on a multi-wavelength fiber laser, belonging to the technical field of fiber-optical communication and signal processing. The tunable microwave photon band pass filter is structurally characterized in that: the output end of a pump source is connected with a port a of a wavelength division multiplexer; a port c of the wavelength division multiplexer is connected with the input end of an erbium-doped fiber; a port b of the wavelength division multiplexer is connected with a port b of a coupler I; a port a of the coupler I is connected with an ordinary single mode fiber; the port b and a port c of the coupler I are connected with a port a of the wavelength division multiplexer and a port a of a coupler II respectively; etc. Based on the multi-wavelength fiber laser, the tunable microwave photon band pass filter can be used for apodization by utilizing a birefringence fiber environment, and then realizes high side lobe suppression ratio by utilizing phase strength conversion (PM-IM). Compared with other microwave photon filters, the tunable microwave photon band pass filter has the advantages of simple structure, low cost, capability of realizing band pass filtration and higher side lobe suppression ratio, tunable band pass, capability of working stably at normal temperature, and the like.

The invention belongs to the technical field of photoelectricity, and particularly relates to a tunable dual-passband microwave photonic filter realization device and method based on stimulated Brillouin scattering. A laser is adopted as a light source; signal light and pump light are generated by an optical coupler branch; a signal light branch is used for loading a to-be-filtered microwave signal through electro-optical phase modulation; a pump light branch generates tunable dual-wavelength pump light by utilizing a Brillouin scattering effect in a single-mode optical fiber and double-sideband suppressed-carrier modulation in a double-parallel Mach-Zehnder modulator; and the conversion from phase modulation of corresponding frequency components in the signal light to intensity modulationis realized by utilizing an absorption spectrum of the double-wavelength pump light in a high-nonlinearity optical fiber, so that a dual-passband microwave photonic filter with a narrow line width, ahigh out-of-band rejection ratio and high stability is realized, wherein the central frequency positions of two passbands are continuously tuned in the same direction by changing the frequency of a radio-frequency signal loaded to the double-parallel Mach-Zehnder modulator, and in addition, a passband interval can be changed by changing optical fibers with different Brillouin frequency shift quantities.

The invention provides a generator of optical chaotic signals for broadband. The generator of optical chaotic signals for broadband comprises a shifting register module, a signal modulation module, a microwave photonic filter, a nonlinear transformation module, a sampling quantitative module and a clock control module. An input end of the signal modulation module is connected to an output end of the shifting register module. An input end of the microwave photonic filter is connected to an output end of the signal modulation module. An input end of the nonlinear transformation module is connected to an output end of the microwave photonic filter. A first input end of the sampling quantitative module is connected to an output end of the nonlinear transformation module while a second input end is connected to an output end of the clock control module. An output end of the sampling quantitative module is connected to a second input end of the shifting register module. A first input end of the shifting register module is connected to the output end of the clock control module. According to the generator of optical chaotic signals for broadband, system status can be completely decided by an initiative value of the shifting register, so that problems in the prior art that synchronization robustness of an analog chaotic system is poor and the bandwidth of digital chaotic signals is narrow are solved.

The invention relates to a microwave photon filter structure which can achieve a negative coefficient and belongs to the field of high-capacity microwave photon communication. The structure consists of a tunable light source (1), a 3db beam splitter (2), a semiconductor amplifier SOA (3), an attenuator or an amplifier (4), a coupler (5), a circulator (6), a Bragg grating (7) and an optoelectronic detector (8). The microwave photon filter structure has the advantages that the characteristic of achieving the negative coefficient of the microwave photon filter is achieved, and finally a light signal passing through a photodiode is converted into a radio frequency signal so that the function of filtering the radio frequency signal in an optical domain is realized directly.

The invention relates to a method for implementing a microwave photonic filter based on a photonic crystal. A bent waveguide integrated coupling beam splitter and a slow light waveguide delay line are used on the same photonic crystal, so that a system function of the filter has the bandpass filter characteristic of trapped wave depth of 10dB in a free frequency spectral range of 130 GHz at 1,550 nanometers; and the function of filtering residual edge bands of a light generation millimeter wave signal can be realized. By using a bidimensional photonic crystal structure compared with an optical fiber ring structure, the size of the filter can be greatly reduced; and the method is favorable for minimizing and integrating the device.

The invention provides a multi-parameter measurement system based on a micro-structure optical fiber interference microwave photon sensing method and method. The system mainly comprises a broad-spectrum light source (1), an optical filter (2), a 3dB optical fiber coupler (3), an adjustable optical delay line (4), an adjustable optical attenuator (5), a micro-structure optical fiber ring (6), a 2*2optical fiber coupler (7), an interference sensing unit (8), a spectral analyzer (9), an electro-optic modulator (10), a dispersion unit (11), a photodetector (12) and a vector network analyzer (13).By combining the optical fiber interference structure and the micro-structure optical fiber ring, multi-parameter sensing can be realized; and besides, in combination of the microwave photon filter,conversion from spectral measurement to frequency domain measurement is realized, the sensing sensitivity is thus greatly improved, and the simultaneous multi-parameter measurement ability is also achieved.

The invention discloses an optical all-pass filter. The optical all-pass filter comprises a first optical coupler, a second optical coupler, a first coupling grating, a second coupling grating, first, second, third and fourth optical phase shifters and a microring. By use of frequency response characteristics of the microring, two ways of signals with adjustable amplitudes and phases are transmitted into the microring from two different ports of the microring respectively and are output at the two ports of the microring after being subjected to interfered beam combination. Different system phase response spectrum widths are realized by changing the coupling state of the microring, system amplitude response is a constant unrelated to frequency through adjustment of the amplitudes and phases of the two ways of signals, so that the optical all-pass filter is obtained. On the basis of the optical all-pass filter, the invention discloses a microwave photonic filter with a high Q value and an ultrahigh inhibition ratio and a microwave photonic phase shifter with a broad work frequency range and no sinking of amplitude response in the work range.

The invention provides an angular velocity measuring device based on a tunable optoelectronic oscillator. The angular velocity measuring device comprises a laser source, a first polarization controller, an electro-optic modulating element, an optical circulator, a second polarization controller, a first polarization beam splitter/combiner, a Sagnac ring, a dispersion element, a third polarizationcontroller, a second polarization beam splitter/combiner, a fourth polarization controller, a fifth polarization controller, a first segment of optical fiber, a second segment of optical fiber, a third polarization beam splitter/combiner, a photoelectric detector, a microwave amplifier, and a power divider. According to the angular velocity measuring device, the Sagnac interferometer is embedded into a microwave photonic filter, so that phase change caused by Sagnac effect is converted into the center frequency of the microwave photonic filter, and change of optoelectronic oscillator output microwave signal frequency is induced. The tunable range of the microwave photonic filter is usually at GHz scale, and the optoelectronic oscillator is capable of generating high quality microwave signals, so that the system is capable of increasing angular velocity measuring sensitivity, and widening the dynamic range at the same time.

The invention discloses a microwave photon filter which comprises a radio frequency amplifier, an erbium-doped fiber amplifier, a tunable optical attenuator, a microcavity coupling system, a spectrumanalyzer and a photoelectric detector. Narrow-linewidth optical carrier wave emitted by a tunable laser passes through a polarization controller and then is processed by DP- MZM into double-side-bandlight wave, and after the double-side-band light wave is amplified by the erbium-doped fiber amplifier, the light power of the double-side-band light wave entering the micro-cavity coupling system iscontrolled by the tunable optical attenuator; wherein an optical signal output by the micro-cavity coupling system is divided into two paths, one path enters the spectrum analyzer for monitoring sideband information of the optical signal in real time, and the other path enters a VNA for monitoring a radio frequency spectrum of the optical signal after passing through the photoelectric detector; meanwhile, the VNA outputs a radio frequency signal, and the output radio frequency signal is loaded to the DP-MZM through an orthogonal mixer after passing through the radio frequency amplifier, and modulation of a sideband is realized. The microcavity coupling system is obtained by attaching the microsphere structure to the conical region of the second conical optical fiber in an over-coupling manner.