363 results about "Optical frequency comb" patented technology

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 a full-locking integrated microcavity optical comb based on coherent population trapping spectral lines, and belongs to the technical field of integrated microcavity optical combs. The full-locking integrated micro-cavity optical comb comprises a laser generation module, a frequency reference subsystem and a micro-cavity optical comb system. The laser generation module is used for generating two paths of laser, the frequency reference subsystem modulates one path of laser, a modulated optical signal is emitted into the atomic gas chamber system, and after transmission light is demodulated and subjected to phase-locked amplification processing, an optical frequency signal and a microwave signal which are locked to an atomic spectral line are obtained; and the optical frequency signal is fed back to the laser generating module to realize optical frequency locking. And the microcavity optical comb system adopts a microwave signal generated by the frequency reference subsystem as a frequency reference, and modulates the other path of laser to serve as pump light to enter the optical microcavity, so that optical comb output of a soliton state in the optical microcavity is realized. According to the invention, a single quantum system is taken as a reference, the problem of full locking of the micro-cavity optical frequency comb is effectively solved, and the system integration degree is relatively high.

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 a method and a system for measuring gravitational potential by a satellite-air-ground optical clock time-frequency comparison system. According to the method for measuring the gravitational potential, an optical clock superior to 110-18 orders of magnitude serves as the basis, a free space time-frequency comparison link based on an optical frequency comb serves as a bridge, the optical clocks among the satellite, the air and the ground are connected, high-precision time-frequency transmission is carried out, a gravity frequency shift signal is accurately extracted through time-frequency comparison of a remote clock, and the gravitational potential is measured. And then the gravity potential difference of the position where the remote clock is located is obtained by using a gravity frequency shift equation, and the gravity potential difference between air and ground or between any ground stations is determined.

The invention discloses an ultra-wideband femtosecond optical parametric oscillator capable of being quickly tuned, and relates to the technical field of optical parametric oscillators. The oscillator comprises a frequency doubling device, an optical parametric oscillator resonant cavity device and a dispersion compensation chirp mirror pair module. According to the invention, the original phase matching bandwidth is further broken through by adopting a non-collinear phase matching mode that the transmission included angle between the pump light and the signal light is 2.5 degrees, and rapid wavelength tuning can be realized only by finely tuning the cavity length under the condition that the angle of the nonlinear crystal is not adjusted; the broadband tunable optical parametric oscillator can break through the bottlenecks in the aspects of wavelength tuning range, wavelength tuning speed and the like of the existing near-infrared optical parametric oscillator, and provides a novel light source with larger wavelength tuning range and higher tuning speed for the fields needing broadband tunable light sources, such as spectroscopy, micro-nano processing, optical frequency combs and the like.

An optical comb generator receives light from at least two continuous wave laser sources, produces a different frequency comb from each laser source, and produces an output that it the simultaneous combination of the different frequency combs. The different frequency combs span different frequency bands, but at least partially overlap in frequency with an adjacent comb in a region of overlap. A spectral filter produces a filtered output that has at least one pair of tones from the region of overlap, the pair of tones comprising one tone from each of two adjacent combs. Feedback control based on the filtered output is applied to adjust the light entering the comb generator such that the frequencies and phases of the pair of tones from the region of overlap are aligned. In this way, the multiple different overlapping combs are stitched together to form a single seamless comb spanning a broader frequency range.

The invention discloses a DP-MZM-based reconfigurable mixer with phase shift and image rejection functions, and belongs to the field of microwave photon signal processing. By adjusting an input radio frequency signal and a direct current bias voltage of the DP-MZM1, four different LO frequency doubling and mixing functions can be realized. By controlling the angle alpha between the polarization direction of the polarization analyzer and one axis of the modulator, the phase of the generated signal can be flexibly tuned in the range of 0-360 degrees. When combined with the optical frequency comb, the multi-channel multi-band frequency conversion system can be expanded into a multi-channel multi-band frequency conversion system with independent phase tuning capability by utilizing the channel switching and frequency slot selection functions of the wavelength selection switch, and parallel output of various frequency mixing results can be realized. By adjusting the phase difference between the two-channel output signals, I / Q mixing, double-balanced mixing and image rejection mixing can be configured. The scheme is not influenced by direct current bias drift, the system complexity is reduced, and the frequency conversion efficiency is improved.

The invention discloses a distributed MIMO (Multiple Input Multiple Output) integrated system and method based on a reconfigurable notch chaotic optoelectronic oscillator, belongs to the field of microwave photons, and solves the problems of spectrum resource conflict, difficulty in multi-node synchronization, discrete inductance functions and the like. According to the system, a plurality of independent chaotic OEOs are combined with an optical frequency comb to drive an FIR filtering effect, MIMO chaotic signals with reconfigurable notch frequency points and quantity are generated, and dynamic allocation of spectrum resources is realized. The notch frequency band is used as a communication channel embedded modulation signal, and supports multi-spectrum sharing with 2.4 G, 5G, Wi-Fi and the like; a non-notch frequency band is reserved as a radar signal, and the range resolution is improved by using the broadband characteristic of the chaotic waveform. The star topology optical network expands the coverage area of a distributed system, and a centralized processing architecture reduces the complexity of multi-node collaboration. The invention provides an integrated solution of high-precision environment perception and high-reliability communication for smart cities, Internet of Vehicles and the like, and is suitable for dense urban areas with resource shortage and dynamic multi-service environments.

The invention discloses a multi-band enhanced infrared optical comb spectrum rare gas detection system in a hollow cavity of building glass, which is characterized in that a line scanning optical frequency comb light source module and a reflective array module jointly form a virtual enhanced cavity to enhance the optical path of an emitted fan-shaped optical comb light beam so as to improve the detection precision; rapid switching of multi-band gas is achieved through an electric filter wheel according to sequential control so as to detect different gases, gas data in a hollow cavity are collected in real time by combining the high-speed collection capacity of a dual-band area array detection module, and a concentration distribution cloud chart of argon and krypton is rapidly constructed based on a data terminal processing module; the detection efficiency and accuracy of the gas in the glass hollow cavity are greatly improved, the synchronous operation of space scanning and wave band switching is realized, and multi-dimensional data of the concentration, the position and the impurity content of multiple gases can be measured and obtained at a time; a polarization filtering function and a temperature field compensation algorithm are integrated, and the detection precision under outdoor strong light and temperature difference environments is ensured.

The invention provides a start key type soliton micro-comb multi-line multiplexing system and a control method, and the system comprises a first soliton micro-comb generation and control module, a second soliton micro-comb generation and control module, a distance measurement module, a gas spectrum analysis module, a communication module and a processing module. The first soliton micro-comb generation and control module and the second soliton micro-comb generation and control module respectively generate a first soliton optical frequency comb and a second soliton optical frequency comb; the distance measurement module, the gas spectral analysis module and the communication module respectively output distance measurement data, gas spectral analysis data, a modulation signal and a local oscillation signal based on the first soliton optical frequency comb and the second soliton optical frequency comb; and the processing module receives the distance measurement data, the gas spectral analysis data, the modulation signal and the local oscillation signal and outputs a distance measurement result, a gas spectral analysis result and a modulation result. The system is simple in structure and operation, narrow in laser line width and excellent in performance, has no special requirements on the environment, and has reliability and robustness.

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.

The invention discloses a device for generating Mach-Zehnder interference, a photo-thermal spectrum gas sensing device based on the device and a detection method, and belongs to the technical field of laser spectrum gas sensing. The interference device sequentially comprises an optical frequency comb and a first light beam splitter on a light transmission path; a movable arm reflector group is arranged on the light path of one light beam B in the two light beams split by the first light beam splitter, the path of the light beam B is changed through the movable arm reflector group, the light beam B intersects with the light path of the other light beam C, and a beam combiner is arranged at the intersection; the movable arm reflector group is connected with a driving mechanism, the driving mechanism is used for driving the movable arm reflector group to do linear motion, and the track of the linear motion is parallel to the straight line where the light beam B is located. The interference device does not need to use a local oscillator optical comb and a signal optical comb to carry out multi-heterodyne interference, can directly use the moving speed of a movable arm reflector group in a Mach-Zehnder interference structure to calculate a down-conversion factor, and maps each longitudinal mode of the signal optical comb in an optical frequency to a radio frequency component one by one.

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.

A covering sheet according to the present invention is used for covering an adherend. The covering sheet includes a first surface and a second surface. The first surface faces the side opposite the adherend. The total light transmittance is 70% or more. The image clarity in a transmission method using an optical frequency comb having a width of 2.0 mm is 5.0% or more. The specular gloss on the first surface with an incident angle of 60° is 30 or less. The maximum spectral transmittance at a wavelength of 300-350 nm is 1.0% or less.

An optical frequency comb generation system comprises an optical waveguide, which in turn comprises a length defining an elongated direction of the waveguide, and first and second reflector portions along the length and arranged to reflect light within the waveguide. A weak reflector portion is between the first and second reflector portions along the length of the waveguide and has a reflectivity less than the reflectivity of the first and second reflector portions. The weak reflector portion is arranged to shift wavelengths of resonances of light within the waveguide.

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 discloses a vehicle-mounted dual-optical-comb system for outdoor testing, comprising an oscillator module, a power amplifier module, a frequency conversion module, a gas measurement module, a signal detection, acquisition, and processing module, and a vehicle-mounted platform module. The oscillator module generates two optical frequency comb signals with slightly different repetition frequencies. The power amplifier module amplifies the two optical frequency comb signals. The frequency conversion module outputs a combined dual-optical-comb beam. The gas measurement module enables the dual-optical-comb beam to interact with the gas to be tested in an open environment. The signal detection, acquisition, and processing module receives the optical signal absorbed by the gas to be tested, converts it into an electrical signal, and acquires and processes the electrical signal to obtain the absorption spectrum information of the gas to be tested. The vehicle-mounted platform module is used to fix and install each module. The advantages of this invention are: stable operation, strong resistance to environmental interference, low power consumption, and suitability for long-term vehicle-mounted operation.

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 an on-chip integrated optical frequency comb generation structure and an optical frequency comb generation method, the structure is formed by heterogeneous integration of a laser chip and an integrated optical microcavity chip, and the integrated optical microcavity chip comprises a polarization beam splitter, two ring filters, an Add-drop type microcavity and two output ports; the polarization beam splitter is used for dividing laser injected by the laser chip into a TE mode and a TM mode, and the TE mode and the TM mode have different power ratios and are injected into the two ring filters respectively. The two ring filters are respectively provided with a heating electrode for controlling the size of the passing wavelength, and the two ring filters have different diameters for transmitting different wavelengths; the Add-drop type microcavity is used for generating an optical frequency comb, and a heating electrode is arranged above the microcavity and used for controlling the resonant wavelength passing through the microcavity. The problems that an existing optical frequency comb debugging system is large and debugging is complex can be solved, the size of the microcavity optical frequency comb can be greatly reduced, and power consumption is reduced.

The invention provides a system and method for enhancing the spectrum demodulation rate of a dual-optical-frequency comb, and the system comprises a circulation light path which carries out the light splitting of excitation pulse light which is inputted to the circulation light path and corresponds to a first repetition frequency, thereby enabling one part of the excitation pulse light to be outputted towards a unit to be detected, and enabling the other part of the excitation pulse light to circulate along the circulation light path; the to-be-tested unit is used for modulating the excitation pulse light and outputting processing signal light carrying dynamic spectrum information generated based on an actual dynamic spectrum of the to-be-tested unit; the light combining unit is used for coupling the processing signal light and the sampling pulse light and outputting coupled signal light; the photoelectric detector performs light field cross-correlation-based detection on the coupled signal light and outputs a periodic electric signal; and the data acquisition and processing unit processes the periodic electric signal to obtain an actual dynamic spectrum corresponding to the unit to be detected. The detection efficiency is at least improved.

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.

This invention relates to a dual-comb control system for a terahertz quantum cascade laser, comprising a first terahertz quantum cascade laser, a second terahertz quantum cascade laser, a first T-type biaser, and a second T-type biaser. The first terahertz quantum cascade laser operates in optical frequency comb mode, while the second terahertz quantum cascade laser operates above a threshold current. The first and second terahertz quantum cascade lasers emit terahertz light from each other. The first terahertz quantum cascade laser also functions as a detector to detect a mixing signal. The state of the mixing signal is switched by changing the power of the radio frequency signal generated by the radio frequency source. This invention enables the switching of the mixing signal between chaotic, unstable, and dual-comb states under high drive current, significantly improving the spectral width and application scenarios of the dual-comb system based on the quantum cascade laser.

The application discloses a kind of based on functional echo wall mode optical microbottle cavity Full light tuning controllable optical comb generation method. Including 1550nm narrow line width continuous wave laser, single-mode optical fiber, erbium-doped fiber amplifier, polarization controller, optical isolator, functional microbottle cavity-fiber taper coupling system, optical attenuator, optical spectrum analyzer and 1550nm power adjustable laser. The unique axial characteristics of echo wall mode microbottle cavity are used, the free spectral range of microcavity is reduced, the axial mode microcavity optical frequency comb with small free spectral range is generated, and based on full light tuning method, functional microbottle cavity is prepared, and the axial mode microcavity optical frequency comb generated is tuned by photo-thermal material titanium dioxide, and significant spectral range tuning is realized. The application solves the limitation that WGM microcavity optical frequency comb cannot be effectively tuned due to large free spectral range, and helps the practical application in the field of microcavity optical frequency comb optical communication, optical frequency synthesis and the like.

The application discloses a microwave photon frequency hopping signal generation device and method based on an optical switch and belongs to the technical field of optical communication. The application is composed of a light source, a beam splitter, an optical frequency comb generator, an electro-optical frequency shifter, an acousto-optic modulator, a digital frequency synthesizer, a filter array, a signal control unit, an electrically controlled high-speed optical switch, a beam combiner and a photoelectric detector. The application separates optical frequency comb teeth by using an ultra-narrow bandwidth optical filter, selects and opens the frequency hopping signal generated by the local light beat frequency through the optical switch, and can generate a high-speed high-order high-stability frequency hopping signal compared with the prior art.

The invention relates to the technical field of satellite communication, and discloses a multiband local oscillator signal generation system and method, and the system comprises a laser, an optical splitter, a first optical modulator, a second optical modulator, an arbitrary waveform generator, an optical coupler, and a signal generation module. The optical splitter divides an optical carrier generated by the laser into first carrier light and second carrier light; the arbitrary waveform generator converts the digital signal into a digital baseband signal to be modulated; the first optical modulator modulates the first baseband signal to the first carrier light to obtain a first optical frequency comb; a second optical modulator modulates a second baseband signal to second carrier light to obtain a second optical frequency comb; the optical coupler couples the first optical frequency comb and the second optical frequency comb into a laser signal; the signal generation module converts the laser signal into a local oscillator millimeter wave signal. Dual-coherent optical frequency combs with different comb tooth intervals are generated through modulation of digital signals with different bit rates, tuning of local oscillation signals is achieved, and the requirement for multi-frequency local oscillation is met.

The invention relates to an intermediate infrared micro comb generation system and method, in particular to an intermediate infrared micro comb key starting type generation system and method based on a negative thermo-optic effect. In order to solve the problems that a traditional mid-infrared light frequency comb is limited in size, weight, power consumption and repetition frequency, and the mid-infrared band faces the defects that the light source tuning rate is low, the micro-cavity quality factor is low and the key device performance is poor, the invention provides the mid-infrared light frequency comb. The intermediate infrared micro comb key starting type generation system based on the negative thermo-optic effect comprises a pumping unit used for providing pumping light, a microcavity unit used for generating a nonlinear four-wave mixing process and the negative thermo-optic effect, and a detection unit used for receiving an intermediate infrared micro comb and recording time domain information and frequency domain information of the intermediate infrared micro comb. Meanwhile, the invention provides a key-starting type generation method of the mid-infrared micro comb based on the negative thermo-optical effect, which is self-starting, wide in spectral bandwidth, high in repetition frequency and high in stability based on the system.

An interferometric resonator optical gyroscope includes an optical frequency comb generator configured to generate an optical frequency comb. Optical signals representative of the optical frequency comb pass through an optical resonator in different directions, and a rotation rate is determined based on the extent of interference between the optical signals. Parameters of the optical frequency comb generator can be controlled by a control servo based on an intensity of the optical signals after propagating in the optical resonator. Utilizing an optical frequency comb generator reduces the bias error during gyroscope operation.

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.