623 results about "Microwave photonic" patented technology

The invention discloses a microwave photonic transceiver based on coherent optical frequency combs. A signal optical frequency comb and a local oscillator optical frequency comb which are coherent are generated through a seed light source module and are each divided into two paths through two beam splitters; for a transmitting module, one path of the signal optical frequency comb is taken and each comb tooth is separated through a de-multiplexing module, a to-be-transmitted intermediate frequency signal is loaded through electro-optical modulation, the modulated signal optical frequency comb and one path of the local oscillator optical frequency comb are combined, and a high-frequency transmitting signal is obtained through photo-electric detection; for a receiving module, the other path of the signal optical frequency comb directly loads a receiving signal through an electro-optical modulator and sends the receiving signal to a signal light input end of an optical mixer, the other path of the local oscillator optical frequency comb is input into a local oscillator light input end of the same optical mixer, and two paths of orthogonal output light signals of the optical mixer are taken to carry out channel cut and coherent detection respectively. The microwave photonic transceiver disclosed by the invention has large real-time processing bandwidth and large dynamic range, and the system consumption is effectively reduced.

The invention discloses an optical device measuring method and device based on double sideband modulation, which belongs to the technical fields of optical device measuring and microwave photonics. An optical double sideband modulation method is used to modulate a radio frequency signal to a first optical carrier signal, so as to generate a double sideband modulation signal. The double sideband modulation signal passes through an optical device to be measured to carry out beam combining with a second optical carrier signal. Frequency difference is between the second optical carrier signal and the first optical carrier signal. A photoelectric detector is used to carry out beat frequency on the signals after beam combining. The amplitude information of a +1 order sideband signal and a -1 order sideband signal in the beat frequency signals is extracted. The frequency of the radio frequency signal is scanned, so as to acquire the broadband amplitude frequency response of the optical device to be measured. The invention further discloses an optical device measuring device based on double sideband modulation. According to the invention, the system complexity and the cost are reduced; the measuring range and the measuring efficiency are greatly improved; and more importantly, a new direction is opened up for an optical device measuring technology.

The invention belongs to the field of microwave photonics, and discloses a system and method for frequency tunable microwave phase shifting. The method comprises the following steps that after a continuous light carrier is splitted, one beam of the continuous light carrier is processed by a MZ Mach-zehnder, and double-sideband optical signals restrained by the carrier are produced; the other beam of the continuous light carrier is processed by a phase modulator, and phase-shifted light carrier signals are produced; two beams of light signals are combined in a wave mode, one one-step sideband is removed through a tunable micro-ring filter in a filtering mode, a frequency-moved carrier signal and a phase-shifted carrier signal are obtained, photovoltaic conversion is carried out through a photoelectric detector, and a phase shift microwave electrical signal is produced; the resonant frequency of the tunable micro-ring filter is equal to any one-step sideband of the two one-step sidebands output by the MZ Mach-zehnder by changing the frequency of an input voltage drive signal and the resonant wavelength of the tunable micro-ring filter, and the frequency of the phase shift microwave signal is changed. The system and method for the frequency tunable microwave phase shifting is stable in output performance, fast in phase shift adjusting response, small in output microwave range fluctuation and continuously adjustable in wide frequency range.

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.

The invention discloses a microwave photon mixing method and system based on local oscillator frequency doubling, and belongs to the fields of optical communication and microwave photonics. The microwave photon mixing system based on local oscillator frequency doubling is formed by utilizing a double-polarization double-parallel mach-zehnder modulator through combination with devices such as a laser, a front polarization controller, a microwave 90-degree coupler, a rear polarization controller, an optical fiber polarizer, an adjustable optical band-pass filter, an erbium-doped fiber amplifier,a photoelectric detector and the like. The system adopts second-order local oscillator sideband and first-order radio frequency sideband beat frequencies, and mixing processing based on local oscillator frequency doubling can be realized; on one hand, the frequency requirement of a mixing system on a local oscillator signal is reduced, and on the other hand, due to the fact that a single-sidebandmodulation mode is adopted, stray signals can be effectively reduced. In addition, the mixing method can realize switching of up conversion and down conversion by changing a direct current bias voltage, and can be used for time-sharing transmitting and receiving of radio frequency.

The invention provides a high non-linear optical fiber excited Brillouin scattering effect and amplitude ratio based microwave frequency measurement method and device and belongs to the technical field of microwave photonics. The device provided by the invention is composed of a tunable laser, a coupler, a phase modulator, a strength modulator, a vector network analyzer, an opto-isolator, a high non-linear optical fiber, a circulator, an erbium-doped optical fiber amplifier, a microwave signal source, a DC voltage stabilizing power source and a photoelectric detector. The frequency range of to-be-detected microwave signals can be enlarged through increasing bandwidths of the strength modulator and the phase modulator and enlarging the scanning range of the vector network analyzer and measurement precision can be improved through reducing noise in optical links and increasing the magnitude of energy transfer of excited Brillouin scattering effect. According to the invention, an amplitude ratio function curve is constructed based on the high non-linear optical fiber excited Brillouin scattering effect and a frequency value of to-be-detected microwave signals is obtained through the amplitude ratio function curve. Therefore, the measurement precision is improved.

The invention discloses a microwave photon receiving method, and belongs to the technical field of microwave photonics. Firstly, the received radio frequency signal is sent to one radio frequency input port of a dual-drive-Mach-Zehnder modulator; an optical modulation signal outputted by the dual-drive-Mach-Zehnder modulator is divided into two paths, and one of the paths forms a photoelectric oscillation loop which is fed back to the other radio frequency input port of the dual-drive-Mach-Zehnder modulator, wherein oscillation frequency of the photoelectric oscillation loop is close to carrier frequency in the radio frequency signal and sufficient to enable the photoelectric oscillation loop to work under an injection locking mode; DC bias voltage of the dual-drive-Mach-Zehnder modulator is adjusted so that phases between input signals on the two radio frequency input ports are non-orthogonal; and the optical modulation signal outputted by the other path is photo-electrically converted so that a down-conversion base band or an intermediate frequency signal is obtained. The invention also discloses a microwave photon receiving device. The device is high in conversion efficiency, low in loss, simple in structure and low in cost.

The invention discloses a totally positive dispersion cavity mode-locked all-fiber laser which is a fiber laser structure with high repetition rate and power, simple structure and high efficiency and is an all-fibermode-locked ultrashort laser pulse laser with stable environment and novel structure. The all-fiber laser takes rare earth doped fiber as a laser gain medium, works in a totally positive dispersion area, uses a polarizing beam splitter to split light, uses a band-pass type long-period fiber grating filter for wavelength selectivity of a mode-locked laser centre and spectral filtering light pulse compression of mode-locked laser and takes a semiconductor saturable absorber as fiber laser structures. The totally positive dispersion cavity mode-locked all-fiber laser has picosecond and femtosecond light impulse length polarizing laser output and lasers with the wavelengths longer than 1 micrometer and can be used for pumping-detecting ultrafast light physical experiments or the environmental monitoring and the microwave photonics and biophysics detection of a molecular system, double-wavelength pumping-detecting ultrafast light physical experiments, frequency-combining light radiation generation, coherent anti-Stokes Raman scattering microscopy, micromachining, and the like by being amplified by a high-power fiber amplifier.

The invention relates to a broadband multichannel channelization system and an implementation method based on an optical frequency shift, and belongs to the technical field of microwave photonics. Aninterference effect between electrooptical modulators and the optical frequency shift characteristic are utilized, and multi-channel division and high-rejection ratio same-intermediate-frequency frequency conversion of broadband microwave signals are completed. The invention proposes the broadband multi-channel channelization method based on the optical frequency shift by combining optical frequency shift channelization and I/Q down-conversion. According to the broadband multi-channel channelization method provided by the invention, a single-frequency laser is combined with a double-sided bandfrequency shift to complete the channel division of a broadband signal; and the output of several two-way same-intermediate-frequency signals which are mirrored to each other through the I/Q down-conversion is realized, which not only avoids the defect that light filtering out-of-band rejection capability is poor in traditional channelized receiving, but also avoids the defect that high-quality coherent optical comb implementation is complex in channelized receiving based on an optical frequency comb.

The invention discloses an ultra-wideband receiver device based on microwave photonics and a realizing method thereof. The realizing method comprises the following steps: dividing an optical signal output by a laser light source into two paths, wherein one path is used for generating an optical frequency comb with uniformly-spaced frequencies by adopting an external modulating mode, and the other path is used for modulating a to-be-received radio frequency signal through an electro-optical modulator and synthesizing the optical signal of the optical frequency comb; enabling the synthesized signal to pass through a tunable narrow bandpass filter for filtering out optical frequency carried with a to-be-detected signal and the fixed frequency point of the closest optical frequency comb, performing transformation through a high-speed detector, and obtaining difference frequency by realizing frequency beating and synthesizing of two frequencies, namely obtaining a frequency-converted medium-frequency signal under a to-be-measured signal. According to the ultra-wideband receiver device based on microwave photonics and the realizing method thereof, the optical frequency comb technology in microwave photonics is applied to designing microwave signal receiving; an adjustable optical fiber is combined to realize the ultra-wideband signal receiving and down-converting on the condition of a low-frequency intrinsic signal (2GHz-5GHz), wherein the receiving bandwidth is lower than that of the low-frequency intrinsic signal by dozens of times.

A wavelength division multiplexing based integrated multi-beam optical phased array delay network for a microwave photonic multi-beam phased array radar, consists of N-channel row waveguides, NxM micro-ring beam splitters, an NxM fixed photo-true delay network, M-channel dimmable true delay arrays and M-channel column waveguides; the NxM micro-ring beam splitters are arranged in N rows and M columns; and the NxM fixed photo-true delay network is connected to the NxM micro-ring beam splitters. The invention only needs M adjustable units, and can realize the phased array radar of M array elements and N beams, is simple and flexible in structure control, is high in integration degree, and is large in instantaneous bandwidth and high in resolution.

The invention discloses a microwave photon frequency mixing method, and belongs to the technical field of microwave photonics. The frequency mixing method involves respectively performing photoelectric modulation on radiofrequency signals and local oscillator signals to be mixed, and extracting one first-order sideband signal from modulation signals, obtaining radio frequency first-order sideband signals and local oscillator first-order sideband signals, and performing photoelectric modulation on the two to enable the frequencies of applied optical carrier waves to be the same; and respectively taking the radio frequency first-order sideband signals and the local oscillator first-order sideband signals as the radiofrequency signal input and local oscillator signal input of a 90-DEG light frequency mixer, and performing photoelectric detection on the output signals of the 90-DEG light frequency mixer to obtain frequency mixed signals. The invention also discloses a multifunctional microwave photon frequency mixer. According to the invention, multiple different frequency mixing functions can be simultaneously realized, the stray is small, the linearity is high, and the conversion efficiency is high. Therefore, the method and the frequency mixer are suitable for frequency mixing of large-octave microwave signals.

The invention discloses a microwave photonic down-conversion method based on a dual-drive polarization division multiplexing Mach-Zehnder modulator (PDM-MZM), and solves a problem of poor stability and noise performance in the prior art. The method comprises the following steps of inputting an optical carrier signal; generating a radio frequency signal and a local oscillator signal; setting a direct-current bias voltage of a sub-modulator; generating a modulation optical signal; carrying out beam splitting on the modulation optical signal; detecting the modulation optical signal; and restraining noise by an electric subtraction device. According to the method, the noise is restrained through dual-drive one-time modulation of the PDM-MZM and a difference obtained by the electric subtractiondevice, so that the stability and the noise performance are improved.

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.

A microwave photonics based signal receiving device includes a signal generation module, a first Mach-Zehnder modulator, a dispersion module, a second Mach-Zehnder modulator, and a signal conversion module. The signal receiving device simplifies a structure of the signal receiving device by adopting quadrature demodulation. The signal receiving device demodulates a high-order modulation signal and flexibly adjusts a microwave carrier frequency.

The invention discloses a microwave photonic image frequency rejection mixing method which comprises the steps of: respectively regulating a radio frequency signal and a local oscillation signal which are to be mixed to an optical domain to obtain a light-carrying radio frequency signal and a light-carrying local oscillation signal; and dividing the light-carrying radio frequency signal/light-carrying local oscillation signal into four paths, after respectively carrying out phase shifting on the four paths of optical signals by theta 1, theta 2, theta 3 and theta 4, respectively coupling the obtained optical signals with the light-carrying local oscillation signal/light-carrying radio frequency signal, then respectively converting the four paths of optical signals obtained after coupling into electric signals, and finally coupling the four paths of electric signals together after respectively carrying out phase shifting on the four paths of electric signals by (with reference to the specification) so as to obtain a mixed signal. Theta 1, theta 2, theta 3 and theta 4 for phase shifting meet the relationships that theta 2=theta 1+pi+2pi n1, theta 3=theta 1+pi/2+2pi n2, and theta 4=theta 1+3pi/2+2pi n3, wherein ni (i=1, 2, 3) is an integer; and (with reference to the specification) for phase shifting meets the relationship that (with reference to the specification), wherein ki (i=1, 2, 3) is an integer. The invention further discloses a microwave photonic image frequency rejection mixing device. The microwave photonic image frequency rejection mixing method and device have the advantages of high flexibility, high conversion efficiency, high linearity, high frequency broadband and simultaneous suppression on various strays.

The invention relates to a microwave photonic filter based on a stimulated Brillouin scattering dynamic grating, and a filtering method thereof, and solves the problem that the existing microwave photonic filter is non-reconstructable and unavailable for continuous tuning and has limited pass bandwidth. The microwave photonic filer comprises a first laser, a first Er-doped fiber amplifier, a first isolator, a fiber coupler, a first phase modulator, a microwave source, a Bragg grating filter, a second Er-doped fiber amplifier, a second isolator, a detector, a polarized light splitter, a second laser, a second phase modulator, and a circulator. The filtering method includes: loading microwave signals to be filtered to carrier light transmitted by the second laser, allowing the detector to output the microwave signals after the loaded carrier light passes the Brillouin dynamic grating, and finishing filtering based on the stimulated Brillouin scattering dynamic grating. The microwave photonic filter based on a stimulated Brillouin scattering dynamic grating, and the filtering method thereof are applicable to the microwave photonics field and the photo-communication field.

The invention discloses a microwave photon up-conversion device and method based on a photoelectric oscillator and belongs to the technical field of microwave photonics. The device is composed of a laser source, a first coupler, a first circulator, a first high nonlinearity dispersion displacement optical fiber, an erbium-doped optical fiber amplifier, a first photoelectric detector, a second coupler, a first Mach-Zehnder modulator, a first microwave signal source, a first direct current voltage-stabilized power supply, an optical filter, a second Mach-Zehnder modulator, a second direct current voltage-stabilized power supply, a second circular, a second high nonlinearity dispersion displacement optical fiber, a second photoelectric detector, a microwave amplifier, a double-parallel Mach-Zehnder modulator, a third direct current voltage-stabilized power supply, a fourth direct current voltage-stabilized power supply, a fifth direct current voltage-stabilized power supply, an optical isolator and a spectrum analyzer. A Brillouin frequency shift value f of the high nonlinearity optical fiber is 9.2GHz, and a signal with frequency of f<m> can be up converted to f<m>+18.4GHz, so alow quality and low frequency intermediate signal is converted into a high quality and high frequency signal.