39 results about "Microwave photonics" patented technology

The invention provides an integrated optoelectronic device based on sideband injection locking and used for generating high-frequency microwaves, belonging to the technical field of optoelectronic device preparation of microwave optoelectronics field, particularly relating to an integrated optoelectronic device based on sideband injection locking and used for generating high-frequency microwaves. The integrated optoelectronic device integrates two slave lasers on the same substrate, sequentially extends a lower waveguide layer, a multi-quantum well active layer, a grating layer, an upper waveguide layer, an upper cladding layer and an Ohmic contact layer on the substrate, couples two slave lasers together by a Y branch waveguide or a multi-mode interferometer, thus realizing injection of modulation sideband of external main laser and carrying out injection locking; and heterodyne beat is conducted by the coupling output of the Y branch waveguide or the multi-mode interferometer, thus being capable of obtaining the high-frequency microwave. The integrated optoelectronic device can integrate a main laser and an electro-absorption modulator further and improve the integration further. The integrated optoelectronic device has novel structure, simple preparation process and excellent application prospect in the future field of high-speed communication.

The invention discloses a microwave photonic down-conversion apparatus and method based on a bidirectional cyclic frequency shift, and relates to the field of microwave photonics. The microwave photonic down-conversion apparatus and method aim to solve the defects of small bandwidth, large loss and the like confronted by a traditional electrical frequency converter and the defect that high-frequency electrical local oscillation is needed by an optical frequency conversion technology. The apparatus provided by the invention consists of a laser, a cyclic frequency shift module and a photoelectric detector; and the cyclic frequency shift module includes a 2*2 optical coupler, a polarization controller, a dual-drive electro-optical intensity modulator, an electrical local oscillation source, an optical amplifier, an optical band pass filter and an optical adjustable delay line. In the cyclic frequency shift module, first-order optical sidebands of a to-be-converted radio-frequency signal and an electrical local oscillation signal on an optical carrier simultaneously perform opposite optical sideband movement step by step at a same frequency shift, and at last photoelectric detection isperformed on two opposite frequency shift optical sidebands having nearest frequencies to implement down-conversion of the radio-frequency signal; and with the characteristic of opposite frequency shift of the cyclic frequency shift module, by changing a frequency of the electrical local oscillation source, the wide frequency range under low-frequency electrical local oscillation and the down-conversion of a tunable microwave signal are implemented.

The present invention discloses a double-chirp frequency multiplication signal generating device based on a dual parallel electro-optic modulator, and a method thereof, and relates to the field of microwave photonics and radars. In the device, the dual parallel electro-optic modulator consists of a phase modulator, and two intensity modulators respectively integrated in the upper and lower arms ofthe phase modulator; a continuous optical laser, a polarization controller, a dual parallel electro-optic modulator, and a photodetector are sequentially connected through the optical fiber, and theoptical detector is connected with a bandpass filter through RF cables; electrical signals are input to the two electro-optic intensity modulators respectively; and a double-chirp output electric signal with a multiple frequency and bandwidth is obtained from the output end of the bandpass filter. According to the technical scheme of the present invention, a single-chirp signal with a carrier frequency of C, a single-chirp signal with a bandwidth B and a microwave signal with a carrier frequency of 4C are used to generate a double-chirp signal with a carrier frequency of 2C and a bandwidth of2B; and the device can be used to generate a double-chirp pulse radar signal with a large bandwidth, has the advantages of a simple structure and easy integration, and can be used to effectively improve the range resolution of the radar system.

The invention relates to a radar communication countermeasure integration design based on microwave photonics. The radar communication countermeasure integration design comprises a system light source, an emitting and receiving end adjustable filtering module, an any waveform generating module, an emitting and receiving end modulator module, a light power amplifier module, a system time delay module, an emitting and receiving end end-detection module, a microwave antenna module, a passage receiving/direct collection receiving module, a microprocessor module and the like. The system can realize the function switching of three kinds of information systems of radar detection, digital communication and electronic countermeasure through parameter configuration and chip configuration; through the any waveform generating module, analog signals or digital signals used for three kinds of systems can be generated; the system comprises an emitting loop and a receiving loop; the emitting loop and the receiving loop use identical light sources, so that the system coherence is ensured; meanwhile, the microwave signals are processed in the photonic filed, so that the advantages of high bandwidth and low noise performance are realized. The system can realize the functional integration of the information system; the environment adaptability and reconfigurability of the system can be improved; the system can be widely used in the information technology fields such as ultra-wide band radar, digital communication and electronic countermeasure.

The invention discloses a radio-frequency signal stable-phase transmission method and belongs to the technical field of microwave photonics. A transmitting terminal divides the frequency of radio-frequency signals needing to be transmitted into two frequencies and then conducts photoelectric modulation, and modulated photo-signals are transmitted to a receiving terminal through a first fiber core of a multi-core optical fiber; the receiving terminal divides the received modulated photo-signals into two parts, wherein one part of the photo-signals are transmitted to the transmitting terminal through a second fiber core of the modulated multi-core optical fiber and then transmitted to the receiving terminal through a third fiber core of the multi-core optical fiber, demodulation is conducted on the part of modulated photo-signals, so that first radio-frequency signals are obtained, and demodulation and frequency tripling are conducted on the other part of the modulated photo-signals, so that second radio-frequency signals are obtained; frequency mixing is conducted on the first radio frequency signals and the second radio frequency signals, filtering is conducted on the frequency-mixed signals through a band-pass filter with the band-pass center frequency identical to that of the radio-frequency signals needing to be transmitted, and down-conversion signals with a stable phase are obtained finally. The invention further discloses a radio-frequency signal stable-phase transmission system. The radio-frequency signal stable-phase transmission system is lower in complexity and implementation cost and higher in compatibility.

The invention provides a system and method for generating multicarrier signals with high flatness and high sideband suppression ratios, and relates to the technical field of optics, microwave and microwave photonics. Multicarrier signals with the high flatness and the high sideband suppression ratios are generated in an optical frequency comb manner to solve the existing problem of multichannel microwave radio frequency signal generation problem within wide broad frequency coverage and acquire the multicarrier signal with a large bandwidth, good flatness and large carrier number. The invention provides an SSB-OCS generation method based on three MZMs connected in parallel, wherein two MZMs work in a single sideband modulation mode, and the other MZM works in an even order suppression mode so as to generate SSB-OCS signals with high sideband suppression ratios in combination with optical phase shift control of 90 degrees. Then, with the proposed SSB-OCS signal generation and optical frequency shift loop as a core, an oscillating circuit is formed in the optical domain to perform circular frequency shift so as to generate the multicarrier signals with high flatness and high sideband suppression ratios.

The invention provides an instantaneous frequency measurement method and system with an adjustable measurement range based on a polarization modulator, and relates to the field of microwave photonics.In the system, TE and TM modes of light waves are subjected to constant-amplitude reverse-phase modulation through a light polarization modulator, and relative phase shift is introduced between the TE and TM modes through bias voltage; combining TE mode light waves and TM mode light waves through an optical power divider shunt and a polarizing film; further introducing equivalent dispersion intoupper and lower paths through a dispersion module formed by optical fibers; mapping the frequency information of a to-be-measured signal to phase information caused by dispersion, carrying out the photoelectric conversion through PD, transferring the frequency information to the amplitude of a photocurrent alternating current component, constructing an amplitude comparison function ACF through thealternating current component in a photocircuit, and calculating the frequency of the to-be-measured signal through the ACF function. The system is simple in structure, the measurement range of the system can be changed by adjusting the bias voltage and the polarization angle of the lower branch, and the measurement resolution of the system can be improved by optimizing the slope of the ACF.

The invention discloses a full-optical-wavelength conversion simplifying device and a full-optical-wavelength conversion simplifying method of a polarization multiplexing system without polarization crosstalk. A wavelength conversion structure of polarization diversity is adopted and two polarization beam splitters are used for respectively dividing signal light and pump light into two groups of mutually-orthorhombic polarization films; two baseband data signals are respectively modulated to two mutually-orthorhombic polarization modes of the signal light to form a modulating signal; the modulating signal and the pump light in the same polarization direction are coupled and then are respectively transmitted into two semiconductor optical amplifiers (SOA); and each SOA independently realizes the wavelength conversion in the same polarization direction. According to the full-optical-wavelength conversion simplifying device and the full-optical-wavelength conversion simplifying method, the crosstalk between polarization multiplexing channels, which is caused by the polarization dependence of a gain in polarization multiplexing wavelength conversion of one SOA, can be overcome; the performance of a wavelength conversion system is improved; the wavelength conversion device has a simple structure and the system is easily integrated; and the wavelength conversion device can be applied to a full-optical-wavelength conversion system of polarization multiplexing signals with the different modulating formats.

Disclosed is a microwave photonics based multi-channel signal transmission system for an aperture synthesis radiometer. The system comprises multi-channel receiving front ends, multi-channel optical transmitters, multi-channel optical fibers and optical receivers. The multi-channel receiving front ends receive multi-channel radio frequency microwave radiation signals through antennas, and then amplify the received signals through low-noise amplification modules. The multi-channel optical transmitters modulate the amplified radio frequency signals to light, light signals are transmitted from all the optical transmitters to the optical receivers through the multi-channel optical fibers, then the optical receivers convert the light signals into radio frequency signals to be outputted, and transmission of the multi-channel radio frequency signals of the aperture synthesis microwave radiometer is completed. By adoption of microwave photonics technology, the radio frequency signals of the distributed receiving front ends of the aperture synthesis microwave radiometer are transmitted, amplitude and phase congruency of multi-channel radio frequency transmission are improved greatly. The method is simple to implement and high in reliability, and a critical foundation is laid to future application of the aperture synthesis microwave radiometer.

The invention provides a microwave photon linear transmission method and system and belongs to the field of microwave photonics. Light carriers generated by a laser are input into a polarization multiplexing double-parallel Mach-Zehnder modulator (PM-DPMZM). Dual-tone radio frequency (RF) signals needing to be transmitted pass a 180-degree electric bridge, thereby obtaining two signals with equalpower and phase difference of Pi. The two signals output by the electric bridge are added to a DPMZM-1 and a DPMZM-2 in upper and lower arms of the PM-DPMZM. Through adjustment of six bias voltages inthe modulator, suppression of second-order and third-order nonlinear distortion is realized. Through adjustment of the bias voltages in the modulator, a system can be adjusted to achieve the second-order or third-order optimum suppression effect. Optical signals output by the modulator enter an erbium-doped fiber amplifier for power amplification, thereby compensating insertion losses in a link.The optical signals enter into a photoelectric detector for frequency beating, thereby obtaining signals transmitted by the system. According to the method, nonlinear distortion of a microwave photonlink is effective suppressed.

The present invention discloses a tunable single pass band microwave photonics Hilbert transform filter system that is based on broad spectrum light source polarization processing and combines with spectral notch phase shift and dispersion integral effect. The system comprises an amplification spontaneous emission broad spectrum light source, an optical fiber Bragg grating, a first polarization polarizer, a first polarization controller, a polarization beam splitter, an adjustable light delay line, an adjustable light attenuator, a phase shift optical fiber grating, a polarization beam combiner, a second polarization controller, a polarization modulator, a third polarization controller, a second polarization polarizer, a dispersion compensation module, and a high-speed photoelectric detector that are all connected with the amplification spontaneous emission broad spectrum light source. According to the system, random tuning of the spectrum position of the bandpass Hilbert transform is realized through turned light delay in a broad spectrum microwave band, so that the Hilbert transform of the bandpass microwave signal is realized. In addition, the system output has no base frequency response and no periodic spectral response, and ensures the singleness and immunity of channel selection.

A radiofrequency (rf) signal-processing device offers the possibility of high bandwidth operation. The disclosed device applies principles of microwave photonics and Linear Amplification based on Nonlinear Components (LINC). For some applications, the device may be embodied in an rf amplifier or rf transmitter. In an embodiment, an optical phase modulator is configured to receive an optical carrier signal as input, and further configured so that, when driven by an rf modulation signal, it will produce a complementary pair of optical signals as output. Each of a pair of detectors is configured to convert a respective one of the complementary optical signals to an rf signal. An rf combiner is configured to add the converted radiofrequency signals from the detectors to form an output signal.

The invention provides a remote high-frequency microwave oscillating source in an optical millimeter wave system. 90% of laser generated by a DFB (Distributed Feed Back) laser is input into a 40G modulator via a polarization controller, 10Gbit/s NRZ (Non Return to Zero) data is amplified by an SHF803P and then input into the 40G modulator, and data intensity modulation is implemented on the laser to generate high-speed broadband modulated light; the light is amplified by an erbium doped fiber amplifier, then input into an XTM50, and filtered to obtain a multiplex clock spectrum, and the spectrum is combined with 10% DFB laser to obtain a spectrum of the high-frequency microwave oscillating source; and the spectrum of the high-frequency microwave oscillating source is amplified via a KPS erbium doped fiber amplifier, input to a near dispersion flattened fiber set, and transmitted to a remote base station to form the high-frequency microwave oscillating source, and electrical signals after beat frequency can replace an electric local oscillator source in a millimeter wave uplink system. Backward Raman amplification is employed; and an AQ6319 and an E4440A respectively measure the spectral and electrographic characteristics of signals. The method for generating the remote high-frequency microwave oscillating source can be used as significant reference in researching the optical millimeter wave system in a high bit rate, and can be widely applied to the fields including microwave photonics and fiber communication.