9 results about "Microwave photonic filter" patented technology

The application discloses a microwave photon filter and a control method thereof, and belongs to the field of optical fiber communication. The filter comprises an optical ring cavity, a tunable laser source, an electro-optic intensity modulator, a photoelectric detector and an electric vector network analyzer. The first input end of the electro-optic intensity modulator is connected with the output end of the tunable laser source, the second input port of the electro-optic intensity modulator is connected with the output end of the electric vector network analyzer, and the output end of the electro-optic intensity modulator is connected with the input end of an optical circulator in the optical ring cavity. The output end of the optical circulator in the optical ring cavity is connected with the input end of the photoelectric detector, and the output end of the photoelectric detector is connected with the input end of the electric vector network analyzer. The application can overcome the problem that the device parameters cannot be adjusted after the structure of the microwave photon filter is determined.

The invention discloses an ultra-wideband weak signal detection method and system based on all-optical oscillation and phase-amplitude conversion. The method comprises the steps that spontaneous radiation light generated by an erbium-doped optical fiber amplifier is used as an optical carrier; modulating a weak radio frequency signal to be measured received by an antenna to the optical carrier through an optical modulator to form a modulated optical signal; the modulated optical signal is injected into an all-optical oscillation circuit composed of double loops, the all-optical oscillation circuit generates multimode optical oscillation by adjusting an optical attenuator, and the all-optical oscillation circuit comprises a double-loop interference structure; performing phase-amplitude conversion by adjusting the delay difference of the two light paths in the double loops to form an equivalent microwave photon filter so as to select and amplify the modulated light signal corresponding to the radio frequency signal of the set frequency band; and converting the selected and amplified modulated optical signal into an electric signal, and performing spectral analysis to detect the weak radio frequency signal to be detected.

This invention relates to the fields of optical fiber communication and microwave photonics. Existing tunable dual-passband microwave photonic filters suffer from poor passband stability and cannot meet practical application requirements. This invention provides a narrow-band tunable dual-passband microwave photonic filter using a Brillouin fiber laser. It generates dual-tone pump light to excite the Brillouin using a tunable laser source and an intensity modulator. Combined with a Brillouin fiber oscillator and a cascaded Fabry-Perot cavity, the Brillouin gain spectrum is narrowed to the kHz level. Simultaneously, the different periodic resonant frequencies of the two ring cavities effectively suppress side modes, filtering out the desired frequency band signal. Furthermore, by synchronously tuning the center frequencies of the two passbands of the filter by changing the pump light wavelength, and simultaneously controlling the output frequency of the signal generator, the frequency interval between the two passbands is changed, ultimately realizing a narrow-linewidth tunable dual-passband microwave photonic filter.

A diaphragm-type optical fiber micro-vibration measurement apparatus and method based on a single-pass band microwave photonic filter. The apparatus comprises a broadband light source module (1), a three-port circulator (2), an AU diaphragm optical fiber micro-vibration sensor (3), an erbium-doped optical fiber amplifier (4), a polarization controller (5), an electro-optical modulator (6), a power supply module (7), a radio-frequency source module (8), a dispersion compensation optical fiber (9), a photoelectric detector (10), a data acquisition card (11) and a computer (12), wherein the broadband light source module (1) is connected to one port of the three-port circulator (2) by means of an optical fiber connection line.

The invention discloses a device and a method for measuring omnidirectional vector bending by using a double-tap microwave photonic filter. According to the device, a multi-core fiber bragg grating is adopted as a bending sensor, a double-tap microwave photonic filter based on a Mach-Zehnder interferometer structure is constructed, and reflected signals of a middle core fiber bragg grating and any one core shift fiber bragg grating are adopted as optical tap signals of the double-tap microwave photonic filter. The wavelength drift of the fiber Bragg grating caused by bending is mapped into the time delay inequality change of the two optical taps, so that the curvature is detected. The measuring device has high measurement resolution and temperature insensitivity, can realize 0-360-degree omnidirectional vector bending measurement, is easy to implement, has a relatively compact structure, has wide application prospects in the fields of structural health monitoring, three-dimensional shape sensing, intelligent robot posture recognition and the like, and is suitable for popularization and application.

This invention discloses a wide-tunable single-passband microwave photonic filter and its construction method. The filter includes a light source device for generating a supercontinuum light source, comprising a generator, an RF power amplifier, a DFB laser, a first erbium-doped fiber amplifier, a first variable optical attenuator, and a highly nonlinear fiber connected in sequence. An optical filter for selecting a certain width of supercontinuum light source is connected between the light source device and a MZI structure for spectral segmentation of the supercontinuum light source. The MZI structure is connected to a photodetector via a single-mode fiber and a second erbium-doped fiber amplifier. The photodetector is connected to the MZI structure via a vector network analyzer. This application features a simple structure, low cost, and the constructed complex coefficient filter eliminates the fundamental frequency response.

The invention discloses a reconfigurable multi-frequency-point high-precision microwave photonic filter based on a multi-channel narrow-band optical filter chip. Based on a multichannel narrow-band optical filter chip, a laser is introduced as a light source, a phase modulator generates a modulated optical signal, a photoelectric detector converts a filtered optical signal to a radio frequency domain for output, and a vector network analyzer provides the radio frequency signal and performs radio frequency domain analysis on the output signal; the multi-channel narrow-band optical filter chip comprises a cascaded asymmetric Mach-Zehnder interferometer which receives and separates modulated optical signals; the square-wave high-order micro-ring resonator array and the tunable high-Q micro-ring resonator array respectively receive and process the upper sideband optical signal and the lower sideband optical signal; and the coupling module combines the processed upper and lower sideband optical signals, generates a filtered optical signal and outputs the filtered optical signal. According to the multichannel narrow-band optical filter chip provided by the invention, by dynamically regulating and controlling the amplitudes and phases of the optical carrier and the optical sideband, a microwave photonic filter with multi-frequency-point band-pass / band-stop mode switching and continuous tuning of the bandwidth, the extinction ratio and the center frequency is realized.

The present application relates to narrow bandwidth filter, due to the limited gain bandwidth of erbium-doped fiber, the delay device such as optical fiber affects the period of transfer function in frequency, limited to the Brillouin frequency shift amount of material, the structure of traditional optical fiber ring resonator limits the narrow threshold of stimulated Brillouin scattering gain, the present application provides a kind of switchable Brillouin frequency shift fiber laser high frequency narrow band microwave photon filter, by using the laser generated by switchable Brillouin frequency shift fiber laser and the modulation light coupling, after beating, the narrow bandwidth microwave photon Brillouin filter of narrow bandwidth laser filtering can be realized;Brillouin frequency shift interval selection structure is accessed in switchable Brillouin frequency shift fiber laser, and then the purpose of Brillouin frequency interval selection is achieved.The present application utilizes switchable Brillouin frequency shift fiber laser, the working frequency of narrow linewidth laser output is selected by Brillouin frequency shift interval, and then single passband high frequency narrow bandwidth laser filtering is realized.

A microwave photonic filter, MWP filter, for bandpass filtering. The MWP filter includes a distributed feedback resonator structure comprising a first resonant cavity and a second resonant cavity, wherein the distributed feedback resonator structure is configured such that an input optical signal is filtered by the first resonant cavity and second resonant cavity to generate a filtered output optical signal. The MWP filter further includes a first micro heater configured to adjust the temperature of the first resonant cavity and a second micro heater configured to adjust the temperature of the second resonant cavity. The MWP filter further includes at least one of: a general heater configured to adjust the temperature of the distributed feedback resonator structure; and a tuneable continuous wave laser source, wherein the MWP filter is configured to tune a wavelength of light generated by the tuneable continuous wave laser source and used by the MWP filter.