187 results about "Frequency comb" patented technology

The invention provides a broadband tunable low-phase-noise photo-generated microwave signal source and device, and relates to the technical field of photo-generated microwaves. According to the invention, a low-frequency optical pulse and a high-frequency microwave signal are respectively input into the electro-optical sampling phase-locked loop; and the electro-optical sampling phase-locked loop determines the synchronization error of the optical pulse and the microwave signal based on the phase difference between the optical pulse center point and the microwave signal zero crossing point. And taking the synchronization error as a feedback signal, and continuously adjusting the frequency and the phase of the microwave signal by the voltage-controlled oscillation module until the frequency and the phase are synchronized with the Nth harmonic of the optical pulse. By setting different initial frequencies of the voltage-controlled oscillation module, microwave signals with different integral multiple optical pulse frequencies can be obtained, and broadband tuning of photo-generated microwave signals is realized. Furthermore, the repetition frequency of the frequency comb is locked through beat frequency of two beams of reference laser and two adjacent comb teeth, the stability of the reference laser is transmitted to the optical pulse, and the stability of the reference laser is further transmitted to the microwave signal through synchronization of the optical pulse and the microwave signal, so that the phase noise of the photo-generated microwave signal source is reduced.

Disclosed in the present invention are a dual electro-optic frequency comb-based laser tracking interferometric spatial coordinate measurement system and method. Multiple target mirrors are identified by means of a vision module, to guide a rotating mirror to direct laser light toward each target mirror individually. A laser tracking interferometric ranging module obtains a tracking error of the laser beam deviating from the center of the target mirror to be used for closed-loop tracking control. A light source module outputs single-frequency laser light traceable to a gas absorption peak. By controlling a light source modulation module to enable or disable an electro-optic phase modulation drive signal, dual electro-optic frequency combs or dual-frequency continuous-wave laser light is outputted. In a tracking state, the laser tracking interferometric ranging module respectively uses the two light sources to measure the absolute distance and the relative displacement of a target mirror, and the real-time distance between the target mirror and an original point is computed by means of distance fusion; the elevation angle and the azimuth angle of the target mirror are obtained in real time by means of an azimuth angle and elevation angle measurement module; tracking control and coordinate computation are carried out by means of a tracking control and signal processing module and a computer, and finally three-dimensional spatial coordinates of all the target mirrors are measured.

The invention relates to the technical field of laser ranging, in particular to a double-optical-comb hybrid ranging device which comprises a signal detection optical path system and a signal demodulation optical path system. Wherein the signal detection optical path system comprises a first optical frequency comb, a first optical isolator, a first optical collimator, a first beam splitter prism, a reference mirror, a Faraday rotator, a convergence mirror and a target reflector; the signal demodulation optical path system comprises a second optical frequency comb, a second optical isolator, a second optical collimator, a half-wave plate, a second beam splitter prism, a third beam splitter prism, a first polarization controller, a first photoelectric detector, a reflector, a polarization beam splitter prism, a second polarization controller and a second photoelectric detector. A third polarization controller; and a third photoelectric detector. According to the invention, three ranging technologies of asynchronous optical sampling ranging, multi-heterodyne interference ranging and synthetic wavelength ranging are fused, and the problem that a large ranging range and high ranging precision cannot be simultaneously considered in the ranging process is solved.

The invention discloses an on-chip time-frequency transmission system and method based on an octave optical comb and an electro-optical modulation optical comb, and the method comprises the steps: constructing a chip-based optical reference cavity through the technologies of vacuum optical cement, photoresist backflow and the like, and achieving an on-chip ultra-stable laser through a phase modulator and a reflection separation optical path; an on-chip laser source pumping micro-ring resonant cavity is utilized to generate an octave optical frequency comb, frequency multiplication is carried out on the on-chip laser source pumping micro-ring resonant cavity and an additional laser source to realize detection and locking of carrier envelope offset frequency (fceo), frequency beating is carried out on the on-chip laser source pumping micro-ring resonant cavity and the on-chip ultra-stable laser device to realize frequency beating (fbeam) locking, and the laser source is utilized to generate an electro-optical modulation optical frequency comb through a circulating phase modulator to realize frequency beating and locking of the on-chip ultra-stable laser device. And the optical time frequency is locked with the locked octave optical comb, is sent to a far end after polarization control and light amplification, and simultaneously receives an electro-optical modulation optical comb at the far end and performs linear light sampling, so that the transmission of the optical time frequency is realized. The optical fiber or space optical link time-frequency transmission device can realize optical fiber or space optical link time-frequency transmission, and has the advantages of low overall noise, high transmission precision, compact structure, small size, low power consumption and the like.

Disclosed herein is an optical frequency comb generator for a distributed acoustic anomaly detection system. The system can include a continuous wave frequency modulated laser source configured to generate a laser signal. The system can include an acousto-optical modulator configured to modulate the laser signal by altering an amplitude and / or frequency of the laser signal based on an RF drive signal applied to the AOM, and to output an optical pulse with multiple frequency sidebands based on the modulation. The output can form an optical frequency comb usable detecting and locating acoustic anomalies within a structure under observation.

The invention discloses an on-line detection method for volatile organic compounds in waste gas, and belongs to the field of waste gas emission monitoring, the detection method comprises the following specific steps: I, starting a quantum cascade laser frequency comb of a middle infrared band, calibrating various parameters of the quantum cascade laser frequency comb, and ensuring to cover a characteristic absorption area of the volatile organic compounds in the waste gas; iI, inputting the waste gas into a gas detection chamber through a sampling pipeline, monitoring the state of the waste gas in real time, and dynamically adjusting the conditions of the gas detection chamber according to various collected signals; the device can capture instantaneous fluctuation of waste gas concentration in real time, meets the high-speed dynamic emission monitoring requirement, has extremely high coherence and narrow linewidth, can analyze tiny spectral line differences which cannot be distinguished by a traditional spectrograph, remarkably improves the detection precision and the recognition capability, ensures that a measurement result still keeps consistency and high reliability under different working conditions, and is suitable for large-scale popularization and application. The signal-to-noise ratio is obviously improved, the power drift is reduced, and long-time stable operation is realized.

The invention discloses a cultural relic restoration decision-making method and system based on computer three-dimensional modeling, and relates to the technical field of cultural relic restoration, and the method comprises the following steps: building a unified time baseline, generating a phase reference field, introducing a double-frequency comb interference structure to reconstruct a humidity refraction field, locking a zero-phase anchor point, and forming an initial constraint condition of a scanning path; under an initial constraint condition, an airflow phase gradient is obtained by adopting a Schlenn pilot frequency chromatography method, a nonlinear diffraction nucleus is calculated, and a refraction residual spectrum is output for modeling correction. According to the method, humidity disturbance is recognized through interference measurement and chromatography, real-time compensation is achieved in combination with phase sheath and humidity control, the crack and material characteristics are fused through neural field modeling, the solidification process is played back in combination with a mineralization mechanism, and the three-dimensional modeling precision and the restoration decision scientificity are improved.

Implementations of disclosed systems and methods are capable of changing the frequency or other waveform characteristics dynamically based on receiving feedback about the effect of an electromagnetic pulse radiation on a target electronic device. Various implementations can be configured to emit electromagnetic pulses at a single radio frequency or a plurality of radio frequencies. For example, the frequency of the carrier electromagnetic radiation in a single pulse can change during the pulse interval. As another example, a single electromagnetic pulse can comprise a frequency comb with two or more frequencies.

A system for generating a supercontinuum comprising a frequency comb generator and a waveguide structure coupled to the frequency comb generator. The waveguide structure comprises distinct sections: an untapered input section with specified first cross-sectional outer dimensions, a down-taper transition section leading to a taper waist section with second cross-sectional outer dimensions that are smaller than the first cross-sectional outer dimensions, followed by an up-taper transition section extending to an untapered output section which reverts to third cross-sectional outer dimensions that are larger than the second cross-sectional outer dimensions.

A method for differentiating gas sources based on temperature includes transmitting an optical beam through a plume emitted by a combustion system. The method includes detecting the optical beam, after propagating through the plume, to obtain an absorption spectrum. The method includes determining, based on the absorption spectrum, a first path-integrated concentration of a gas species, a first temperature of the first path-integrated concentration, a second path-integrated concentration of the gas species, and a second temperature of the second path-integrated concentration. The second temperature is different from the first temperature. The method may further include performing an inversion to obtain a sampled quantity of the gas species within the plume. The method may be implemented with dual-comb spectroscopy, in which case the optical beam is formed from two frequency combs having slightly different repetition rates.

The invention discloses a beat frequency comparison device mediated by an optical frequency comb. The beat frequency comparison device comprises the optical frequency comb, a first frequency stabilized laser, a first beat frequency device, a first frequency mixer, a first high-pass filter, a second frequency stabilized laser, a second beat frequency device, a second frequency mixer, a second high-pass filter, a DDS signal generator, a third frequency mixer and a low-pass filter. Frequency-stabilized lasers output by the first frequency-stabilized laser and the second frequency-stabilized laser and an optical frequency comb output by the optical frequency comb are subjected to beat frequency in the first beat frequency device and the second beat frequency device respectively, and first beat frequency and second beat frequency are obtained; the first beat frequency and the second beat frequency are mixed with the carrier envelope offset frequency of the optical frequency comb, and a first sum frequency and a second sum frequency are filtered out; the first sum frequency obtains a synthetic frequency through direct digital frequency synthesis; the second sum frequency and the synthetic frequency are mixed in the third mixer, and then the difference frequency is filtered out through the low-pass filter. According to the invention, beat frequency comparison of frequency-stabilized lasers with different wavelengths can be realized, and the influence of the stability of the optical frequency comb is avoided.

The invention provides a mid-infrared optical frequency comb. The mid-infrared optical frequency comb comprises a near-infrared optical frequency comb seed source of a polarization-maintaining all-fiber structure; the all-fiber nonlinear amplification and pulse compression module is connected with the near-infrared optical frequency comb seed source through a polarization maintaining fiber and is used for amplifying the power of the seed light and compressing the pulse width after generating a linear chirped pulse; the all-fiber nonlinear spectrum broadening module is connected with the all-fiber nonlinear amplification and pulse compression module through a polarization maintaining fiber and is used for broadening a laser spectrum; the difference frequency module is used for receiving the laser pulse processed by the all-fiber nonlinear spectrum broadening module and generating an intermediate infrared laser pulse through intra-pulse self-difference frequency; wherein the seed source, the all-fiber nonlinear amplification and pulse compression module and the all-fiber nonlinear spectrum broadening module are connected through a polarization maintaining fiber to form an all-fiber integrated structure. By adopting the scheme, the anti-interference capability of the system can be enhanced, miniaturization and high operation reliability are realized, the debugging process is simplified, and the difference frequency efficiency is improved.

A measuring device (10) for determining the position of a component (226) in a system (200) comprises a radiation generator (24) configured to generate a measuring radiation (22e) with at least two discrete radiation frequencies (36; 136), which are selected comb frequencies (38) of a frequency comb structure (37), wherein the frequency comb structure is defined by at least two comb parameters, of which the first comb parameter comprises a uniform frequency spacing (42) of the comb frequencies and the second comb parameter comprises a frequency offset of the frequency comb structure from a reference frequency, an optical resonator (16) comprising resonator frequencies (17) and a measuring target (14) assigned to the component and configured to measure distances by irradiating the measuring target with the measuring radiation, and a coupling module (32),which is configured to couple the at least two discrete radiation frequencies to two of the resonator frequencies and for this purpose comprises a radiation detector (50) for detecting a radiation sample (22r) of the measuring radiation branched off from the optical resonator and a control device (54), wherein the control device (54) is configured to generate a control signal (56) for the radiation generator from the radiation sample detected by the radiation detector, which control signal comprises a specification (42v) for at least one of the comb parameters.

The invention provides a terahertz frequency comb generation verification method and system based on an optical fiber microcavity optical frequency comb, and the method comprises the steps: injecting a continuous wave laser into an optical fiber microcavity resonator to generate a stable Kerr optical frequency comb, enabling the Kerr optical frequency comb to work in a single soliton state or a soliton crystal state, and obtaining an optical frequency reference with low phase noise. Furthermore, spectrum selection is performed on the optical frequency comb, multiple groups of optical comb tooth pairs comprising comb teeth of different orders are actively selected, and the optical frequency difference of each group of comb tooth pairs is directly converted into an electric signal in a terahertz frequency band by utilizing a beat frequency effect of a photoelectric detector. A plurality of terahertz electric signals generated by different comb tooth pairs are integrated to form a multi-channel terahertz frequency comb. The method allows a plurality of discrete and frequency-controllable terahertz signal channels to be generated in parallel on a single optical platform through one-time optical processing and photoelectric conversion, so that multichannel terahertz frequency comb generation is realized.

The invention provides a frequency stabilization device and a frequency stabilization method of an optical frequency comb, and relates to the technical field of optics, the optical frequency comb can be generated based on a self-injection locking principle through an optical frequency comb unit comprising a laser and a first micro-resonator of which the end faces are coupled, and then the optical frequency comb is generated through the first micro-resonator. Through the control system, the second micro-resonator is used as a reference resonator, the laser with the specific frequency of the optical frequency comb and the resonance mode of the second micro-resonator can be locked, and the frequency stability of the laser with all frequencies of the optical frequency comb is improved.

The present invention proposes a multimode laser frequency comb device and a degenerate multimode control method. The device includes a diamond crystal, an optical frequency degeneration module, and a degeneracy control module. Based on the multimode laser frequency comb device, the present invention applies stress to the diamond crystal according to the degenerate multimode control method, regulating the lattice constant of the diamond crystal, thereby regulating the degeneracy of Raman vibrations and controlling the optical frequency degeneration mode. This converts an existing single-mode laser comb into a multimode laser comb output. This can generate a multimode optical frequency comb consisting of a single mode or multiple single-mode frequency combs with spectral width spacing. This multimode optical frequency comb has the advantages of wide wavelength coverage, large spectral spacing, and multiple spectral width spacings that are tunable.

The application belongs to the technical field of optical communication and relates to a frequency-shift-free microwave photonic channelized receiving device, which comprises a carrier light frequency comb generating unit, a local light frequency comb generating unit, an electro-optical modulation unit, an optical phase shift unit, a channel selection and spectrum processing unit and a plurality of photoelectric conversion units. The received broadband radio frequency signal is modulated on each comb tooth of the carrier light frequency comb through the electro-optical modulation unit, and the frequency alignment between the optical local oscillator and the required receiving sub-channel can be realized based on the "vernier" effect caused by the different free spectral ranges of the carrier light frequency comb and the local light frequency comb and the inherent frequency alignment of the same pump laser. The mirror image sub-channel suppression is realized based on the opposite optical phase shifts on both sides of the pump light. The application has a simple structure, omits the frequency shift and special modulation structure required for frequency alignment, effectively suppresses the inter-channel crosstalk problem in the channelized receiving process, and can flexibly increase the channelization quantity according to actual needs.

A metrology system may include a dual frequency comb source providing a first comb beam having a first repetition rate and a second comb beam having a second repetition rate; a beam splitter to generate one or more dual-frequency comb illumination beams from the first comb beam and the second comb beam; and a beam combiner to form a dual frequency comb illumination beam from the first comb beam and the second comb beam. The system may further include an illumination subsystem to illuminate a sample with the dual frequency comb illumination beam through an objective; a light collection subsystem to collect sample light from the sample with the objective lens; and a detector to capture a radio frequency signal based on the sample light. The system may further extract spectral measurement data associated with the sample from the radio frequency signal and generate a metrology measurement based on the spectral measurement data.

The invention discloses a free space optical communication system based on a structured optical frequency comb, and belongs to the field of optical communication. Comprising an optical frequency comb generation system, a signal coding system, a spatial light modulation and demodulation system and a signal receiving system. The optical frequency comb generation system is used for modulating input continuous laser into an adjustable optical frequency comb with high repetition frequency, short pulse width and high power; the signal coding system is used for separating the light with different wavelengths in the optical frequency comb, independently coding the light with each wavelength, and finally combining the light with different wavelengths again; the spatial light modulation and demodulation system is used for coupling the Gaussian beam in the optical fiber into a free space and converting the Gaussian beam into structured light, demodulating the structured light after the structured light is transmitted to a receiving end and re-coupling the structured light back to the optical fiber; the signal receiving system is used for receiving and analyzing the optical signals. According to the invention, the optical frequency comb and the structured light are combined, and the problem that optical signals are easily influenced by atmospheric turbulence in free space optical communication can be effectively solved on the premise of ensuring large communication capacity.

This invention provides a self-heterodyne detection system capable of stably and over long periods of time measuring broadband laser linewidths. [Solution] The present invention discloses a self-heterodyne detection system. The system may include a frequency comb light source that generates light, a photodetector that detects the light, an electrical spectrum analyzer connected to the photodetector that analyzes the frequency and wavelength of the light using the detection signal of the photodetector, an interferometer including an input coupler provided between the frequency comb light source and the photodetector to receive the light, a branch waveguide branched by the input coupler, and an output coupler connected to the branch waveguide, and a programmable filter provided in the branch waveguide to select the peak wavelength of the light.

The invention discloses a micro-cavity optical frequency comb and a structural parameter determination method thereof, relates to the technical field of optical frequency combs, and aims to solve the problems that in the prior art, a traditional optical frequency comb is limited in structural regulation dimension, and an existing design method is difficult to efficiently and accurately achieve matching of spectrum requirements and structural parameters. The micro-cavity optical frequency comb comprises an input / output waveguide and a grating-assisted nested micro-ring cavity. The input / output waveguide is coupled with the grating-assisted nested micro-ring cavity; the grating auxiliary nested micro-ring cavity comprises an outer micro-ring, an inner micro-ring and a grating; the grating is formed on the outer micro-ring or the inner micro-ring; the outer micro-ring and the inner micro-ring are coupled to form a nested resonant structure; structural parameters corresponding to the grating-assisted nested micro-ring cavity are obtained through light field steady-state verification based on trained reverse neural network prediction; the trained reverse neural network is obtained based on the forward neural network. The method is used for realizing efficient and accurate design of the microcavity optical frequency comb and meeting the target spectrum requirement.

The invention discloses a high-performance optical comb laser based on heterogeneous material integration and multi-effect fusion, belongs to the technical field of optical communication and laser devices, and aims to solve the problems that a traditional optical comb laser is difficult to start tuning, low in power efficiency, large in line width or limited in bandwidth and the like. A scheme of heterogeneous integration of a III-V group gain material, a low-loss Si3N4 waveguide and a high-electro-optical coefficient barium titanate (BTO) material is adopted, an outer cavity chip comprises a high-Q-value annular resonant cavity, an electro-optical comb is generated by modulating the annular resonant cavity, then a Kerr comb is excited, and the optical comb is amplified through gain. According to the invention, three mechanisms of electro-optical modulation, Kerr effect and semiconductor light amplification are fused, and based on device topological structure innovation and unit device optimization, the problems are solved, the on-chip frequency comb performance is significantly improved, and the optical comb laser with excellent starting and tuning performance, high power, large bandwidth and narrow line width is realized.

The application discloses a kind of visible band tunable femtosecond pulse laser generation device, including input side single-mode optical fiber jumper component, visible light frequency comb generation module, collimating lens, tunable filter module, focusing lens and output side single-mode optical fiber jumper component in turn along laser light path, visible light frequency comb generation module includes germanium core optical fiber, germanium core optical fiber is tapered optical fiber, including core and cladding, core is SiO2 core of GeO2 doping concentration 98mol.%, cladding is SiO2 cladding, the input end of germanium core optical fiber is fused with the output end of input side single-mode optical fiber jumper component.The device has high integration, and through the structure of all-fiber realizes integrated all-fiber and tunable stable, accurate single-wavelength femtosecond pulse laser output, does not need to adjust optical path frequently to complete coupling in use process, saves manpower and material resources, and the laser generator structure is small and exquisite, compatibility is good, and it is convenient to be applied in large-scale complex optical system.

The application discloses a kind of fast quantitative distributed optical fiber vibration detection method and system based on frequency comb, belong to optical fiber sensing field technical field, method includes: S1, design target frequency comb, including the comb tooth interval Δf of the target frequency comb is designed C And the initial phase of the target frequency comb;S2, the target frequency comb is converted into time domain signal, and the time domain signal is modulated on probe light, obtains modulated time domain optical carrier signal;S3, the modulated time domain optical carrier signal is carried out optical domain frequency shift and probe pulse modulation, obtains modulated frequency comb pulse sequence;S4, the frequency comb pulse sequence is input to the optical fiber FUT to be measured, and quantitative distributed optical fiber vibration detection is carried out.The application realizes the modulation of target frequency comb on probe pulse, compresses single detection time, to improve the frequency response capability to external disturbance, can realize the high signal-to-noise ratio detection of dynamic signal.

A movement prediction apparatus including first and second light output devices, a light reception device, and a processor. The first light output device outputs output-light having a spectral component of a first optical frequency comb of which a frequency comb interval is a first interval. The second light output device outputs reference light having a spectral component of a second optical frequency comb of which a frequency comb interval is a second interval. The light reception device receives combination light that is a combination of the output-light, reflection light that is the output-light reflected by a flying object rotor wing, and the reference light, and measures a distance to the rotor wing based on the combination light. The processor calculates a rotation amount that represents a rotational speed of the rotor wing based on a change amount of the measured distance, and predicts a movement of the flying object.

LIDAR distance measuring device (10), comprising: a laser (12) for generating a laser beam, a frequency comb generator (14) configured to generate at least one optical frequency comb signal (37) based on the laser beam, a signal splitting unit (16) which is configured to split the optical frequency comb signal (37) into different optical signal channels (34), each of which is assigned a respective wavelength range, a channel matching unit (18) which is configured to change at least two optical signal channels (34) in their relative position to each other, a transmitting unit (20) which is configured to send light associated with the modified optical signal channels (36) as transmitting light (22) into a measuring area (24), a receiving unit (26) for receiving transmitted light reflected from objects (28) in the measuring range (24) as received light (30), and a signal processing unit (32) which is configured to determine a distance to the object (28) based on the received light (30) and in particular at least a part of the transmitted light (22).

The present disclosure provides a device suitable for generating a frequency-stable microcavity optical frequency comb, comprising: a light source part configured to emit a light beam; a beam splitting device configured to split the light beam emitted by the light source part into a plurality of first light beams; a light source frequency determination unit connected with a first output port of the beam splitting device, the adjustment frequency being determined based on the absorption of the first light beams by atoms in the light source frequency determination unit, and the light source part adjusting the frequency of the emitted second light beams based on the adjustment frequency; a resonant microcavity connected with the light source frequency determination unit, the second light beams generating a first microcavity optical frequency comb in the resonant microcavity; and a modulation unit arranged between a second output port of the beam splitting device and the resonant microcavity, configured to modulate the second light beams into third light beams with repetition frequency information based on the repetition frequency of the first microcavity optical frequency comb, and the third light beams generating a second microcavity optical frequency comb in the resonant microcavity.

Method for generating a frequency-modulated transmit signal (8) for a transmitting device (5) of a detection device (2) for transmitting the frequency-modulated transmit signal (8) into an environment (3) of the detection device (2), comprising the steps: - Generating a frequency comb (11) using an optical mode-locked source (10) of the transmitting device (5); - Filtering of at least one frequency line (12) in the generated frequency comb (11) by means of a first optical filter device (13) of the transmitting device (5); and - Generating the frequency-modulated transmit signal (8) by means of a photodiode (14) of the transmitting device (5) as a function of the filtered frequency comb (15), wherein the frequency-modulated transmit signal (8) is generated proportionally to the frequency difference to the filtered frequency line (12), wherein at least two frequency lines (12) are brought closer together by means of an optical dispersive element (18) of the transmitting device (5) or at least two frequency lines (12) are pulled further apart by means of an optical dispersive element (18) of the transmitting device (5), wherein the dispersive element (18) is arranged in the beam path after the first optical filter device (13) or the dispersive element (18) is arranged in the beam path before the first optical filter device (13).

The invention discloses a method for obtaining the thickness and refractive index of a film, a test system, a storage medium and application. The method for obtaining the thickness and the refractive index of the thin film comprises the following steps: obtaining an intermediate frequency signal carrying transmission phase information by using two groups of nonlinear transmission line terahertz frequency comb generators and a broadband mixer, and obtaining an actually measured phase curve based on the intermediate frequency signal; constructing an equivalent multi-optical-path interference model of the thin film, performing coherent superposition on multiple reflection components of a measured wave signal in the thin film in a complex field to obtain a complex phase of a total transmission field, and obtaining a phase-frequency change spectrum based on the complex phase as a model phase curve; and an error function of the model phase curve and the actually measured phase curve is constructed, and a parameter combination enabling the error function to take the minimum value is solved by scanning the parameter combination of the refractive index n and the thickness d of the thin film. According to the method, thermal drift or time drift of the phase is avoided, and then calculation errors caused by phase jump are avoided.