285 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.

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.

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.

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.

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.

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.