286 results about "Opto-electronic oscillator" patented technology

Aspects of the disclosure relate generally to a circuit for sustaining an radio frequency (RF) modulated optical signal. The circuit may comprise a self injection locking component having a fiber optic delay line over which a portion of the optical signal propagates. The circuit may also comprise a self phase locked loop component having at least two fiber optic cables having different lengths and over which another portion of the optical signal propagates and a phase detector coupled to the at least two fiber optic cables and configured to determine a phase difference between the signals propagating over one of the respective fiber optic cables. The circuit may further comprise a voltage controlled oscillator configured to generate a stable oscillating signal in response to signals generated by each of the self injection locking and self phase locked loop components, the stable oscillating signal being configured to sustain the optical signal.

An opto-electronic oscillator including a modulator for outputting modulated light and a tunable filter for receiving modulated light output from the modulator.

The invention discloses a stable photoelectric oscillator. The stable photoelectric oscillator comprises a laser device, an electro-optical modulator, a long optical fiber, a photoelectric detector, an amplifier, an electric band-pass filter, an electrically-controlled microwave phase shifter, a high-stability microwave source, a 2*1 wave combiner or directional coupler, a first 1*2 power divider or directional coupler, a second 1*2 power divider or directional coupler, a third 1*2 power divider or directional coupler and a phase locking control module, wherein the phase locking control module comprises a frequency mixer, an electric low pass filter and a servo control module, the output end of the frequency mixer is connected to the input end of the electric low pass filter, and the output end of the electric low pass filter is connected to the input end of the servo control module. According to the stable photoelectric oscillator, an electric injection of the external high-stability microwave source and a phase locking control mechanism are added based on a traditional single-loop OEO structure. Compared with the prior art, the stable photoelectric oscillator has the advantages that insertion loss of an optical link in a resonant cavity is not increased, the high signal to noise ratio of the photoelectric resonant cavity is maintained, and the structural complexity of the stable photoelectric oscillator is lower than that of an existing scheme. The stable photoelectric oscillator is easy to obtain.

Systems and methods for precision phase noise measurements of radio frequency (RF) oscillators are provided. An RF signal under test can be modulated on a continuous wave (cw) laser carrier frequency via generation of modulation sidebands using an appropriate modulator. A photonic delay line can be implemented as a self-heterodyne detection system for the phase noise, allowing for photonic down-conversion of the phase noise measurement to direct current (DC). The self-heterodyne detection system allows detection outside of any 1 / f noise issues. Ultra-low phase noise detection for RF frequencies in a range from below 1 GHz to beyond 100 GHz is enabled with a low noise floor in the whole frequency range. Higher-order modulation sidebands can further reduce the noise floor of the system. Ultra-low noise RF (microwave) output can be generated. The RF signal under test can be generated by a dielectric resonance oscillator or opto-electronic oscillator.

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 laser wavelength adjustment-based opto-electronic oscillator with a tunable frequency and a tunable broadband. The opto-electronic oscillator is characterized in that: a wavelength tunable laser, a polarization controller, a double-arm Mach-Zehnder modulator, a narrowband phase-shifted fiber grating and a high speed photoelectric detector are connected in order by fibers; and radio frequency input ports of the high speed photoelectric detector, a microwave high pass filter, a microwave amplifier, a microwave phase shifter, a microwave coupler, a microwave 3dB quadrature coupler and the double-arm Mach-Zehnder modulator are connected in order by microwave coaxial lines. Besides, a closed opto-electronic oscillation loop is formed by the double-arm Mach-Zehnder modulator, the narrowband phase-shifted fiber grating, the high speed photoelectric detector, the microwave high pass filter, the microwave amplifier, the microwave phase shifter, the microwave coupler, and the microwave 3dB quadrature coupler; and a high quality microwave signal with a tunable frequency and a tunable broadband is generated at another output port of the microwave coupler by adjustinga wavelength of the wavelength tunable laser. According to the invention, the opto-electronic oscillator has advantages of compact structure, fast frequency adjusting speed, and wide tunable frequency domain and the like.

A photoelectric oscillator includes a laser beam projection unit; an optical modulator on an optical path extending from the projection unit, which optical modulator outputs a modulated signal or an optical signal containing a harmonic of the modulated signal and includes a modulation electrode whose resonant frequency band includes the frequency band of the modulation signal; a photoelectric converter for converting the output of the optical modulator to an electric signal; a feedback circuit for selecting from the radio-frequency electric signal obtained from the photoelectric converter an electric signal to be re-supplied to the optical modulator; and an output section for outputting an optical signal containing the modulation signal or a harmonic of the modulation signal or outputting the modulation signal or a harmonic of the modulation signal. A laser beam of sufficient intensity is input from the projection unit to produce a radio-frequency electric signal in the feedback circuit, and the radio-frequency electric signal or an optical signal containing the radio-frequency electric signal or the radio-frequency signal is output from the photoelectric oscillator.

The invention discloses a highly-stable single-mode microwave optoelectronic oscillator. A modulator B (5) is arranged in an optoelectronic oscillator (OEO) loop and driven by a highly-stable microwave source (12), output modes of the oscillator can be chosen through a modulation mode locking process, and edge mode noise is inhibited through gain competition between the modes. Simultaneously a phase-locked loop theory is used for comparing output signals of the OEO with output signals of the highly-stable microwave source (12), a phase (or cavity length of the OEC) for controlling the output signals of the OEO is fed back, and finally stable single-mode OEO output is obtained. The highly-stable single-mode microwave optoelectronic oscillator can achieve frequency stabilization phase lock and single-mode operation of the OEO simultaneously, is simple in structure and low in cost, and has practical value.

An optoelectronic oscillator (OEO) is used to provide a continuous, high Q, modulated signal for a variety of purposes, including a carrier wave for communications, and radar emissions. The OEO of this invention replaces an RF filter in the conventional OEO with an interferometer, preferably a high finesse Fabry-Perot etalon as the mode selector, providing lower phase noise and higher RF frequency stability.

The invention discloses a production method of an optical microwave signal with tunable broadband frequency. The method comprises the following steps: constructing a stable dual-loop low-frequency optoelectronic oscillator; injecting an external continuous lights into the optoelectronic oscillator, implementing the injection locking in a directly modulated laser of a core component of the optoelectronic oscillator to finish the up-conversion process of the optical microwave so as to generate a high-frequency optical microwave signal; implementing the tunability of the optoelectronic oscillator by adjusting the wavelength, optical power and polarization state of the external continuous lights so as to generate the optical microwave signal with needed frequency. By injecting the external continuous lights into the directly modulated laser in the optoelectronic oscillator and then locking an optical carrier wave after the up-conversion is generated under a high-order mode, the high-quality optical microwave signal is produced. The method provided by the invention can be used for producing any high-frequency optical microwave signal based on an injection locking technology by using the lower-frequency electric signal, and the tunability of the microwave frequency can be realized by only controlling the wavelength, polarization state and optical power of the injected continuous lights.

Methods and devices for a coupled optoelectronic oscillator having optical frequency stabilization. The coupled optoelectronic oscillator includes a harmonically mode-locked laser cavity having a Mach-Zehnder modulator for mode-locking and an intracavity Fabry-Perot etalon to allow only one single supermode to lase, a stabilization loop coupled with the Fabry-Perot etalon to detect changes in the laser cavity optical frequency and generate an error signal to compensate for the frequency change to stabilize the mode-locking of the laser frequency stabilization, and an electrical loop between the laser cavity and the stabilization loop for driving the Mach-Zehnder modulator with the coupled optoelectronic oscillator signal.

The invention discloses a frequency multiplication photoelectric oscillator, comprising a light source, a fundamental wave and frequency multiplication double-output light modulator module, an optical detector and a photoelectric loop circuit. The fundamental wave and frequency multiplication double-output light modulator module consists of a mach-zehnder modulator, an optical phase shifter and three optical couplers. The modulation characteristics of the mach-zehnder modulator working at the maximum transmission point and the minimum transmission point are adopted to realize the output of frequency multiplication oscillation signals of the photoelectric oscillator. In order to generate a feedback fundamental frequency microwave signal for maintaining the operation of the photoelectric oscillator, the output light of the mach-zehnder modulator and the other path of light carrier wave after phase shifting are coupled into one path, so as to generate the fundamental frequency microwave signal through coherence interference. The fundamental wave and frequency multiplication double-output light modulator module is integrated on one lithium niobate chip. The frequency multiplication photoelectric oscillator is easy for controlling a working point, can work stably and easily in a temperature change and vibration environment and is lower in cost.

An integrated circuit frequency generator is disclosed. In some embodiments, the frequency generator comprises an electronic oscillator configured to generate an oscillator frequency and calibration circuitry configured to periodically calibrate the electronic oscillator with respect to a reference frequency source. When a primary power source is unavailable, an output frequency is generated from the oscillator frequency, and the reference frequency source is periodically pulse powered-on to calibrate the electronic oscillator.

The invention discloses a compensator and compensation method for transmission delay in optical fiber time frequency transmission. The compensator comprises a central station and a remote terminal, wherein the central station is connected with the remote terminal through optical fibers, the central station comprises a time frequency scale source, a frequency multiplier I, a frequency multiplier II, a filter I, a frequency mixer I, a frequency mixer II, a filter II, a light emitting module I, a combiner, a light receiving module I and an amplifier I, and the remote terminal comprises a wave separator, an optical modulator I, an optical modulator II, a light receiving module II, an amplifier II, a filter III, a phase shifter, a power divider, a light emitting module II and an electrical interface. The compensation method includes the steps that the central station conducts long-distance injection locking on a photoelectric oscillator of the remote terminal, the remote terminal accumulates errors and transmits the errors back to the central station, the central station conducts compensation through phase delay and a fluctuation regulation and control circuit, and therefore the output of the photoelectric oscillator of the remote terminal is locked to the central station. According to the compensator and the compensation method, the asymmetry of two-way delay is eliminated, therefore, the transmission accuracy can not be limited by the measurement accuracy of the system, and accurate long-distance transmission can be conducted.

Disclosed are multiphase oscillators comprising a plurality of delay stages serially coupled in a loop by a plurality of nodes, with the loop being folded to provide two concentric rings of delay stages with equal numbers of allocated nodes. A second plurality of negative-resistance elements are provided, each element having a first output coupled to a node on the first concentric ring and a second output coupled to a node on the second concentric ring. Each such output switches between first and second voltage levels, and provides a negative resistance to a signal coupled to it during at least a portion of the transition between voltage levels. The outputs of an element switch to opposite voltage levels. With this construction, a high-voltage pulse propagates around the loop of delay stages, with a low-voltage pulse propagating behind it. Also disclosed are circuits to control the direction of pulse propagation.

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 full-light-control phased array radar transmitter based on a broadband light source comprises a microwave signal generating part, a signal modulation and delay part and a transmitting part. The microwave signal generating part comprises the broadband light source, a first optical divider, a second optical divider, a first polarization controller and the like. The signal modulation and delay part comprises a second electrooptical modulator, a second optical amplifier, an optical fiber delay network, a second optical combiner. The transmitting part comprises a first wavelength division multiplexer, an optical fiber or an optical cable, a photoelectric detector array and the like. According to the full-light-control phased array radar transmitter based on the broadband light source, microwave signals are generated through an optoelectronic oscillator based on the broadband light source, an external microwave source is omitted, the broadband light source is used for replacing a multi-wavelength laser array, the structure that the wavelength division multiplexer is used for dividing the broadband light source enables the full-light-control phased array radar transmitter to be simple and compact in structure, and cost is lowered.

An injection locked dual opto-electronic oscillator having a master oscillator which generates a high Q RF output signal with a plurality of harmonic signals within a predetermined pass band. A slave oscillator has a modulation input coupled to the output signal from the master oscillator as well as an output signal. The slave oscillator has a cavity length selected to produce a single mode operation within the pass band. An electronic phase shifter in the slave oscillator is adjustable to produce constructive interference at a single harmonic of the output signal from the master oscillator and destructive interference of all other harmonics within the pass band and to bring the slave oscillator into injection locked condition with the master oscillator. Therefore the slave OEO is used as a filter for the spurious radiation generated by the master OEO and at the same time preserves the high Q of the RF carrier signal from the master OEO.

The invention discloses an optoelectronic oscillator based on intermediate frequency selection. The optoelectronic oscillator comprises a local oscillator signal source, a microwave power divider, a laser, a polarization maintaining fiber, a single-mode fiber, an electro-optic modulator, a photoelectric detector, a microwave band-pass filter, a frequency mixer, an intermediate frequency band-pass filter and an intermediate frequency amplifier. Through up-conversion and down-conversion, side mode suppression of an OEO is realized through a narrowband intermediate frequency band-pass filter, so that an OEO loop is allowed to be longer to realize high Q value; and through matching of the polarization maintaining fiber in corresponding length and group delay of the intermediate frequency band-pass filter, influence of phase noise of a local oscillator signal is eliminated. The up-conversion in an OEO structure is realized through a microwave photon link; advantages of wide bandwidth and small insertion loss are realized; and frequency conversion loss can be reduced obviously by improving laser power.

Optoelectronic oscillator systems and an optoelectronic oscillator noise reduction method. One example of an optoelectronic oscillator system includes an optical source positioned at a first end of a fiber-optic path, the optical source being configured to transmit an optical signal along the fiber-optic path, an optical modulator positioned to receive and modulate the optical signal based on at least a reference signal, a retro-reflector positioned at a second end of the fiber-optic path, the retro-reflector being configured to receive and retro-reflect the optical signal, the retro-reflected optical signal having at least a frequency range of inherent fiber noise canceled, and an optical circulator positioned along the fiber-optic path between the optical modulator and the retro-reflector, the optical circulator being configured to direct the optical signal to the retro-reflector and direct the retro-reflected optical signal along a feedback path to a first photodetector to generate the reference signal.

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.

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 present invention details fabrication guidelines of integrated optoelectronic oscillators with frequency and phase stability, having higher frequency selectivity in a relatively small size (compared to the larger size of a higher order electrically realized RF filter), reduced temperature sensitivity, and minimized frequency drift. The integrated photonic components and RF oscillator may use Silicon photonics and microelectronic integration using CMOS and BiCMOS technology, eliminating the need for bulky and / or discrete optical and microwave components.

The invention discloses a photoelectric oscillator based on an optical resonant cavity, and aims to carry out photoelectric oscillation on laser so as to generate high-quality microwave signals. The photoelectric oscillator consists of a laser, a photoelectric modulator, an amplifier, a filter, a photoelectric detector and an optical resonant cavity which form a loop, wherein the loop forms the main structure of the photoelectric oscillator. The photoelectric oscillator disclosed by the invention has outstanding advantages in generating high-quality microwave signals in a light domain, and high-quality microwave signals can be formed through multiple times of oscillation; the optical resonant cavity is adopted to output the microwave signals through multiple times of oscillation, and the invention mainly aims to minimize the photoelectric oscillator; the optical resonant cavity is adopted to replace conventional long optical fibers, so that the photoelectric oscillator has the characteristics of small size, low consumption, stable performance and the like, and is applicable to the field of radio wireless communication and microwave photonics; the optical resonant cavity is realized through coupled prisms and micro disc cavities and thus is relatively stable in property when being compared with an optical resonant cavity realized through coupled waveguide and micro discs.

The invention discloses a vibration sensing device based on a photoelectric oscillator, and the device comprises a laser, a one-in-two optical coupler, an optical phase shifter, a sensing head, a polarization controller, a Mach-Zehnder modulator, a two-in-one optical coupler, an energy-storage optical fiber, a photoelectric detector, a band-pass filter, a radio frequency amplifier, a 3dB power divider, a reference oscillator, a frequency mixer, a low-pass filter, an analog-to-digital converter, and an upper computer. According to the invention, one arm of the Mach-Zehnder modulator serves as the sensing head, thereby improving the sensitivity of vibration signal detection, and improving the detection precision. Compared with other passive optical fiber sensors, the device enables vibration information to be coded on the frequency of the vibration signal not the intensity, so the device is not sensitive to the impact from the power fluctuation of a light source. Compared with an optical fiber based on an optical fiber laser, the device is higher in sensitivity, and the sensitivity of the device is not related with the oscillation frequency. The device can be implemented through a low-cost low-frequency device, and is high in practicality.

A photoelectric oscillator based on a direct-modulation semiconductor dual-mode laser comprises an amplification feedback laser (a) used for producing dual longitudinal mode lasing, a photoelectric detector (b) used for converting optical signals output by the amplification feedback laser (a) into electric signals, a microwave amplifier (c) used for amplifying electric signals detected by the photoelectric detector (b) and a microwave power divider (d) used for injecting a part of the electric signals back into the amplification feedback laser (a). The part of the electric signals is output. According to the photoelectric oscillator, the amplification feedback laser (a) is employed to generate double longitudinal modes; and then dual longitudinal modes are subjected to frequency mixing through the photoelectric detector (b) and converted into microwave electric signals. The signals are amplified and then injected back into the amplification feedback laser (a). Direct modulation is carried out on the signals to form a self-feedback oscillation system, thus forming high-quality tunable microwave output.

The objects of the present invention are to shorten a cavity length of an optoelectronic oscillator and to integrate on a semiconductor or SiO2-substrate. An optoelectronic oscillator 10 have an optoelectronic loop comprising a semiconductor laser 11, an optical waveguide 12 guiding laser light emitted from the semiconductor laser, a photodetector 13 detecting laser light guided by the optical waveguide and outputting an electrical signal, an amplifier 14 amplifying the electrical signal outputted from the photodetector, generating an amplified signal and formed on a semiconductor substrate 15. Laser light emitted from the semiconductor laser 11 is controlled by generated amplified signal and it oscillates with a fundamental oscillation frequency determined by a delay time of carrier in the optoelectronic loop circuit or one of the high harmonic components of integral multiples of a fundamental oscillation frequency.

The invention provides a light and small type ultra-low phase noise photoelectric oscillator and an optical micro-cavity manufacturing method thereof. The oscillator comprises a laser, an electrooptical modulator, an optical micro-cavity, a photoelectric detector, an electric amplifier, an electric filter and an electric coupler. An optical signal output by the laser is subjected to modulation and output by the electrooptical modulator, the optical signal amplification by the optical amplifier, optical delay and optical energy storage by the optical micro-cavity, and the photoelectric conversion by the photoelectric detector. The converted electric signal passes the electric amplifier and the electric filter, and is fed back to the electrooptical modulator through the electric coupler. According to the invention, by use of the photoelectric link de-noising technology, and taking low-loss and high Q value optical micro-cavity as an energy storing element, ultra-low phase noise of the microwave signals output by the photoelectric oscillator is achieved; and by use of the micro type optical micro-cavity, small and light photoelectric oscillator is achieved.

The embodiment of the invention provides a photoelectric oscillator. The photoelectric oscillator comprises a swept source, a phase modulator and a band-stop optical filter. The phase modulator carries out phase modulation for a swept-frequency optical signal to generate a first intermediate signal with positive and negative first-order sidebands; the band-stop optical filter filters away any sideband in the first intermediate signal; the photoelectric detector is connected with the band-stop optical filter to receive an output signal of the band-stop optical filter, to convert the output signal into a periodic swept-frequency microwave signal with the central frequency adjustable and to feed the periodic swept-frequency microwave signal to the phase modulator after the periodic swept-frequency microwave signal is amplified; the swept source, the phase modulator and the band-stop optical filter compose a band-pass swept-frequency microwave filter; the central frequency of the band-pass swept-frequency microwave filter is equal to the difference between the central frequency of the swept source and the central frequency of the band-stop optical filter. Therefore, the embodiment of the invention solves the technical problem of how to generate the periodic swept-frequency microwave signal with low phase noise, good correlation and adjustable central frequency.

The invention discloses a Fourier domain mode-locked photoelectric oscillator. The Fourier domain mode-locked photoelectric oscillator comprises a laser source, a phase modulator, a light notching filter, a photoelectric detector, a power amplifier and a power divider; the laser source, the phase modulator, the light notching filter and the photoelectric detector form a sweeping frequency microwave photon filter; a transmission band of the sweeping frequency microwave photon filter is decided by the difference of the laser source and the light notching filter notching location corresponding wavelength, the sweeping frequency of the microwave photon filter transmission band is realized through the sweeping frequency of the laser source or the light notching filter, and the change of the filter transmission band and the signal are matched with the in the time delay for transmitting a circle in a photoelectric oscillator loop; the Fourier domain mode-locking is realized, and the bandwidth-adjustable chirp microwave signal can be output.