60 results about "Optical frequencies" patented technology

The invention discloses an epoxy resin aging diagnosis method based on electric frequency and optical frequency combined characteristics, and belongs to the technical field of electrical equipment insulation aging assessment. The sum of products of frequency under electric frequency and a dielectric loss angle tangent value and the sum of products of frequency under optical frequency and the dielectric loss angle tangent value are used as characteristic values; the method comprises the following steps: fitting with equivalent breakdown field strength, constructing a quantitative characterization relationship between the equivalent breakdown field strength of an epoxy resin sample and an electric frequency-optical frequency dielectric loss angle tangent value, and evaluating the actual aging degree of the epoxy resin insulating material by calculating the decline rate of the equivalent breakdown field strength, thereby avoiding a large number of repeated breakdown experiments. The aging degree of the epoxy resin insulating material can be accurately and quickly evaluated; the function relationship between the breakdown field strength of the epoxy resin material and the electric frequency-optical frequency dielectric parameters is constructed from two directions, the evaluation index suitable for the aging degree of the whole period is established, and theoretical support is provided for accurate and rapid evaluation of the aging degree of the epoxy resin insulating material.

The invention relates to the technical field of optical fiber communication, and discloses an optical fiber optical frequency relay transmission system and method without a phase-locked loop. The optical fiber optical frequency relay transmission system comprises multiple stages of relay stations which are sequentially cascaded through an optical fiber transmission link, and for each stage of relay station, a first photoelectric detector is used for carrying out beat frequency processing on a current-stage optical frequency signal sent by a current-stage regeneration cavity-stabilized laser and an optical frequency signal received from a previous-stage relay station; frequency mixing and summation are carried out on the current-level beat frequency signal and an optical frequency signal transmitted by an upper-level relay station through the data interaction unit, so that noise accumulation generated in a signal transmission process in a traditional phase-locked loop scheme can be thoroughly eliminated; therefore, the noise item in the optical frequency signal output to the user side is completely counteracted, that is, the high-precision original optical frequency signal is provided for the user side, and long-distance and high-precision optical frequency transmission can be realized on the basis of reducing the complexity of system design.

The invention discloses an optical fiber optical frequency transmission relay system and method based on a spread spectrum technology. The relay system comprises a receiving module, a regenerative laser module and a sending module. The receiving module is used for demodulating the spread spectrum optical signal according to the second pseudo-random sequence to obtain a demodulated optical signal; the spread spectrum optical signal is a signal which is transmitted through an optical fiber link after a preceding stage performs spectrum spreading on the optical signal; the regeneration laser module is used for locking the frequency of the demodulation optical signal to generate a regeneration optical signal and splitting the regeneration optical signal to obtain a return optical signal and a transmission optical signal; the receiving module is also used for modulating the returned optical signal according to the second pseudo-random sequence and transmitting the modulated returned optical signal back to the preceding stage; and the sending module is used for demodulating the post-stage modulation return optical signal to obtain a demodulated return optical signal, carrying out noise suppression and spectrum spreading on the transmission optical signal according to the demodulated return optical signal and a third pseudo-random sequence, and then transmitting the transmission optical signal to the post-stage. By introducing the spread spectrum technology, the second-order Rayleigh scattering signals are filtered out, and the stability and reliability of the system are remarkably improved.

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 discloses a coherent optical frequency signal regeneration amplification system based on optical fiber transmission. The coherent optical frequency signal regeneration amplification system comprises a local narrow linewidth laser which outputs narrow linewidth laser; the first optical fiber coupler couples the narrow linewidth laser to the first acoustic optical modulator and the second acoustic optical modulator respectively; the output of the first acousto-optic modulator and superior transmission light are jointly coupled into a photoelectric detector by a second optical fiber coupler to generate a beat frequency signal; the signal processing module samples the beat frequency signal after conditioning the beat frequency signal, performs phase discrimination on the sampled signal and the digital reference signal to generate an error signal, and generates a first feedback signal and a second feedback signal according to the error signal to be respectively used by the local narrow linewidth laser and the first acousto-optic modulator; performing real-time cycle slip detection on the error signal and repairing a phase abnormal point to generate a third feedback signal to be used by a second acousto-optic modulator; and the second acousto-optic modulator outputs amplified regenerated laser. According to the invention, high-precision optical frequency signal transmission can be realized in a complex and changeable optical fiber environment with large noise.

The embodiment of the application provides a kind of arrayed microcavity blood pressure detection system based on digital light frequency double comb, it is related to optical sensing technical field.The input end of light intensity modulator is connected with laser, waveform generator respectively, the output end of light intensity modulator, polarization controller, on-chip optical microcavity array are sequentially connected;Light intensity modulator is modulated based on electrical modulation signal to single-frequency light, and optical frequency double comb signal is obtained;Optical frequency double comb signal enters on-chip optical microcavity array after polarization controller, on-chip optical microcavity array is pasted to the position of the artery to be measured, and on-chip optical microcavity array includes multiple sensing units, each sensing unit generates an independent pulse signal, and on-chip optical microcavity array obtains sensing signal based on optical frequency double comb signal and the jump extrusion of the artery to be measured position, and signal processing mechanism obtains blood pressure value information based on sensing signal.The detection system can realize the technical effect of improving the accuracy and convenience of blood pressure measurement.

Optical frequency reference apparatus (10) comprising - an atomic vapor cell (1), containing a vapor of reference atoms, said atomic vapor cell (1) comprising a first end (41) having a first window (4) and a second end (61), - a laser source (11) for generating a laser probe beam (3) adapted to excite a two-photon optical transition of said reference atoms, - an optical detector (14), adapted to detect a fluorescence signal emitted by said reference atoms, and - at least one reflective element (5, 15) wherein the laser source (11), the atomic vapor cell (1) and the at least one reflective element (5, 15) are configured such that, in operation, the probe beam (3) enters the atomic vapor cell (1) through said first window (4) at said first end (41) and crosses said vapor of reference atoms until said second end (61) through a defined optical path in a first forward direction (3a), the probe beam (3) is reflected backwards by said at least one reflective element (5, 15) and crosses said vapor of reference atoms a second time through the same defined optical path, in a second direction (3b) opposite to the first forward direction (3a), characterized in that the optical frequency reference apparatus (10) further comprises means (7, 9) for absorbing the reflected laser probe beam (3) exiting from the atomic vapor cell (1) according to the second direction (3b).

A control unit (24-1) stabilizes the frequency of a carrier-envelope offset signal of an optical frequency comb. A control unit (24-2) stabilizes the frequency of a beat signal produced by the interference between measured light from a measured light source (21) and the optical frequency comb. A detection unit (34) detects a frequency interval for each of four operations for which the frequency interval between modes of the optical frequency comb is different. An optical frequency calculation unit (30) calculates first through fourth approximate estimate values for a mode number for an initial operation on the basis of the frequency interval for each of the four operations and calculates the true mode number of the initial operation on the basis of the estimate values to calculate the frequency of the measured light.

An optical comb light source outputs an optical comb having a plurality of modes. The optical comb light source includes an optical comb generating section, an optical frequency changing section, and a mode optical frequency controlling section. The optical comb generating section generates the optical comb. The optical frequency changing section receives a reference wavelength light having a predetermined optical frequency and changes the optical frequency of the reference wavelength light for output. The mode optical frequency controlling section controls a mode optical frequency that is an optical frequency of one mode of the plurality of modes such that a difference between the mode optical frequency and a target optical frequency that is an optical frequency of an output from the optical frequency changing section has a predetermined value. The optical comb generating section changes optical frequencies of the plurality of modes according to the controlled mode optical frequency.

A fibre optic sensing apparatus (400) is described which has an optical output path (403, 405, 404) configured to repeatedly interrogate a sensing optical fibre (402) by launching coherent optical radiation into the sensing optical fibre. A detector (407) is configured to receive optical radiation that is Rayleigh backscattered from the sensing optical fibre and output a detected backscatter signal in response to each interrogation and a processor (408) processes the detected backscatter signal. The apparatus is operable in a frequency swept mode, in which the sensing optical fibre is interrogated with a first set of interrogations of coherent optical radiation having different optical frequencies from one another to acquire, for at least one sensing portion of the sensing optical fibre, a backscatter spectral profile (201) of a measurement value of the detected backscatter signal with frequency across a first frequency range. The processor is configured to combine a plurality of said backscatter spectral profiles (201, 202) to form a reference profile (203) with an effective frequency range greater than the first frequency range

The present application relates to the technical field of optical frequency transfer, and particularly relates to a relay system and method for realizing automatic phase locking of optical fiber optical frequency transfer, which comprises: an optical fiber beam splitter for splitting signal light into two parts; an acousto-optic modulator for frequency shifting; a relay laser for generating regenerative laser; a photodetector for beat frequency between signal light and regenerative laser; a signal processing and discrimination locking unit for processing beat frequency signals and discriminating whether to lock at a target frequency; a control unit for maintaining the locking state of the regenerative laser when it is discriminated that the frequency of the regenerative laser is locked; and outputting the locked regenerative laser to the next optical fiber link after frequency shifting by a third acousto-optic modulator; and the specific method is to realize automatic frequency locking and relocking of the regenerative laser through double beat frequency signal discrimination and feedback control, and to ensure stable relay of optical frequency signals. The present application improves the long-term stability and reliability of the relay system.

The invention provides an optical microphone demodulation method and system based on a digital optical comb, and the method comprises the steps: carrying out the inverse fast Fourier transform of a data sequence of a constant-amplitude pseudo-random phase relation, and converting the data sequence into an analog signal; performing light splitting on the optical signal to obtain two paths of optical signals; one path of optical signal is used as a reference optical signal, and the other path of optical signal is subjected to optical frequency comb modulation through an analog signal to obtain a measurement optical signal; enabling the target sound wave to act on the measurement optical signal, causing the spectral characteristic offset of the measurement optical signal through an acoustic-optical coupling effect, and obtaining an offset optical signal; performing coherent detection on the reference optical signal and the offset optical signal to obtain a detection signal; and sampling the detection signal, and analyzing the target sound wave based on the sampled data. According to the invention, tiny optical frequency change caused by sound signals can be captured, and high-precision application scene requirements can be met; tiny optical frequency deviation caused by extremely weak sound can be clearly distinguished, and high-sensitivity and high-resolution detection of weak sound signals is achieved.

The invention provides an optical frequency scanning interference absolute distance measurement system and a stable reference construction method thereof. The optical frequency scanning interference absolute distance measurement system comprises a measurement interference module, an auxiliary interference module, a frequency stabilization laser reference module and a laser synchronous control and signal resolving assembly. The measurement interference module generates a beat frequency interference signal related to a to-be-measured space distance; the auxiliary interference module generates beat frequency interference signals related to instantaneous optical frequencies of the first tunable laser and the second tunable laser, monitors the optical frequencies of the first tunable laser and the second tunable laser in real time, and corrects frequency sweep nonlinear errors of the first tunable laser and the second tunable laser; a long fiber bragg grating string is arranged on a measuring arm of a Mach-Zehnder interferometer in the auxiliary interference module; the frequency stabilized laser reference module generates a beat frequency interference signal related to the optical path difference of the auxiliary interference module to compensate the optical path drift of the auxiliary interference module; the laser synchronous control and signal resolving assembly resolves a distance value to be measured according to interference signals generated by the three modules.

Ion optical frequency standard automatic control software adopts the design concept of system integration, the system is developed by adopting the LabVIEW language, the whole-process software and hardware control requirement in an ion optical frequency standard experiment is met, and automatic intelligent control is achieved. The method specifically comprises the steps of setting experimental parameters in an ion optical frequency standard experiment, controlling, detecting and reading experimental data of the ion optical frequency standard experiment, carrying out data processing and calculation work such as transition probability calculation and the like, controlling and adjusting the parameters by utilizing PID to realize system closed-loop locking, and storing the experimental data. And a man-machine interaction interface which is simple and beautiful and has high fault tolerance in an interaction mode is designed, so that the method is simple, convenient and easy to use, and the working complexity of an ion optical frequency standard experiment is effectively reduced.

The present disclosure proposes an opto-mechanical pressure measurement system for measuring an ambient pressure level, the system comprising: an optical fiber having a first optical fiber end and a second optical fiber end; an opto-mechanical cavity mounted at the first optical fiber end and composed of a first membrane element and a second membrane element spaced apart from each other, where the first membrane element contacts the first optical fiber end; at least one light beam generating device coupled to the second optical fiber end and configured to generate light beams and direct the light beams onto the opto-mechanical cavity via the optical fiber, each light beam having a particular optical frequency; and a light sensing member coupled to the second optical fiber end, where the at least one light beam generating device is configured to direct a first light beam having a first optical frequency onto the opto-mechanical cavity, where the first light beam is modulated at a modulation frequency within a bandwidth of a mechanical resonance frequency of the second membrane element, wherein the at least one light beam generating device is designed to direct a second light beam having a second optical frequency onto the optomechanical cavity; and wherein the light sensing member is configured to detect a portion of the second light beam reflected by the optomechanical cavity and to determine an ambient pressure around the optomechanical cavity based on a change in the amplitude of oscillation of the second membrane element.

The present invention relates to a molybdenum strontium peroxide second-order nonlinear optical crystal and its preparation and application. The chemical formula of the crystal material is SrMo2O3(O2)4(H2O)2·3H2O, the molecular weight is 545.58, it belongs to the tetragonal crystal system, its space group is , the unit cell parameters are α=β=γ=90°, Z=8, and the unit cell volume is . The molybdenum strontium peroxide crystal material of the present invention has excellent optical properties. Under 1064nm laser irradiation, the powder frequency harmonic intensity is about 3 times that of potassium dihydrogen phosphate crystal, and phase matching can be achieved. The crystal material is not only easy to grow, but also can effectively expand the wavelength range of coherent light sources through optical frequency conversion technologies such as second harmonic generation and optical parametric amplification. In the fields of laser lithography, laser processing, medical diagnosis and treatment, this crystal material shows important application prospects.

The invention provides a distributed optical fiber vibration sensing method and system based on time-frequency distribution, and relates to the technical field of high-precision time-frequency synchronization and optical fiber sensing multi-network integration. A time-frequency reference network distributes an ultra-stable optical frequency signal and a time synchronization signal of a source end node to all receiving nodes through a time-frequency distribution link; the synchronization of optical signal frequencies, phases and time of all nodes is ensured; the vibration sensing network sends optical signals of adjacent nodes to an opposite end through the sensing optical fiber link for beat frequency detection, obtains vibration disturbance signals along the sensing optical fiber link, determines the position of vibration disturbance, and breaks through the bottleneck of a traditional forward transmission distributed optical fiber sensing system in the aspects of monitoring mode and spatial resolution.

A high-precision space-time-frequency comparison system and method based on photo-generated millimeter waves. A master end and a slave end each obtain, by means of heterodyne frequency beating, a millimeter-wave signal from an optical frequency locked to an optical reference consisting of a super-stable laser and an optical atomic clock; the master end and the slave end each send the millimeter-wave signal to the opposite end by means of a spatial link; the master end and the slave end each measure the time difference between a local millimeter-wave signal and the millimeter-wave signal that is received from the opposite end; the slave end can obtain the clock difference between the master end and the slave end by means of a bidirectional comparison principle, thereby implementing bidirectional time-frequency comparison; moreover, the slave end adjusts an optical reference frequency and a phase, such that time-frequency synchronization between the master end and the slave end can be realized. The present invention effectively alleviates the problems of inadequate precision in traditional microwave-based time-frequency comparison methods and relatively low continuous operation rates in traditional optical-carrier-based time-frequency comparison; and has the advantages of a low noise floor, simple structure and high reliability.

The application relates to the technical field of optical fiber communication, and discloses a kind of optical fiber optical frequency relay transmission system and method without phase-locked loop.The optical fiber optical frequency relay transmission system includes: multiple stages of relay stations cascaded in turn through optical fiber transmission link, for each stage of relay station, the optical frequency signal of the stage emitted by the regenerative cavity stable laser of the stage and the optical frequency signal received from the relay station of the upper stage are frequency mixing processed by the first photoelectric detector, the frequency mixing signal of the stage is obtained, and the optical frequency signal transmitted by the relay station of the upper stage and the frequency mixing signal of the stage are mixed and summed by the data interaction unit, the noise accumulation generated in the signal transmission process in the conventional phase-locked loop scheme can be completely eliminated, so that the noise term in the optical frequency signal output to the user end is completely cancelled, i.e. high-precision original optical frequency signal is provided for the user end, and long-distance, high-precision optical frequency transmission can be realized on the basis of reducing the complexity of system design.

A LIDAR system is adapted for performing differential absorption measurements of a chemical compound between two distinct optical frequencies (ν1, ν2), and for measuring a separation distance from an obstacle which is present in a background of a measurement zone where the absorption occurs. An emission optical power value is varied between different time intervals during a radiation emission sequence, in order to allow that the LIDAR system implements an optical fiber technology while having sufficient emission power. The LIDAR system makes it possible to evaluate an amount of the chemical compound which is contained in the measurement zone, as well as a separation distance from an obstacle which is located in the background of the measurement zone.

The invention relates to a 2-halogen ethane sulfonate second-order nonlinear optical crystal and preparation and application thereof, the chemical formula of the crystal material is Na [SO3 (CH2) 2X] (H2O), X = Cl or Br, the crystalline material belongs to a monoclinic system, the space group is Pc, and the cell parameters are alpha = gamma = 90 degrees, beta = 91.86-92.86 degrees, and Z = 2. The powder frequency doubling effects of the non-linear optical crystals Na [SO3 (CH2) 2Cl] (H2O) and Na [SO3 (CH2) 2Br] (H2O) under 1064nm laser irradiation are respectively 0.6 and 0.8 times of that of KH2PO4 (KDP), the powder frequency doubling intensities of the non-linear optical crystals Na [SO3 (CH2) 2Cl] (H2O) under 532nm laser irradiation are respectively 0.1 and 0.2 times of that of beta-BaB2O4 (BBO) crystals, and phase matching can be realized. In addition, Na [SO3 (CH2) 2Cl] (H2O) and Na [SO3 (CH2) 2Br] (H2O) have moderate birefringence (0.09 at-546 nm and 0.106 at-546 nm) and short ultraviolet absorption cut-off edges (190 nm and 208 nm), and millimeter-level single crystals are easy to grow. The wavelength range of the coherent light source can be expanded through optical frequency conversion technologies such as second harmonic generation and optical parametric amplification, and important application value is shown in the fields such as laser frequency conversion and photoelectric information storage.

The optical frequency of one mode of an optical comb can be changed by more than half the repetition frequency of the optical comb. [Solution] The optical comb light source 1 outputs an optical comb having multiple modes. The optical comb light source 1 includes an optical comb generation unit 11 that generates an optical comb, an optical frequency change unit 14 that receives a reference wavelength light having a predetermined optical frequency νcw and changes the optical frequency νcw of the reference wavelength light to output, a mode optical frequency νm which is the optical frequency of one of the multiple modes, and a target optical frequency νcw+f which is the optical frequency of the output of the optical frequency change unit 14. AO The difference between this and the predetermined value (beat frequency) f beat The optical comb generation unit 11 includes a mode optical frequency control unit 18 that controls the mode optical frequency to achieve the desired result. The optical comb generation unit 11 changes the optical frequencies of multiple modes according to the controlled mode optical frequency νm to produce the output of the optical comb light source 1.

Methods, systems, and devices for measuring tilt in semiconductor manufacturing are described. A first set of contacts and a second set of contacts may be formed on the measurement marker. Based on forming the sets of contacts, a stack of nitride and oxide materials may be deposited over the first set of contacts. Subsequently, a set of cavities may be etched through the stack of nitride and oxide materials to the set of contacts, such that a respective cavity may be etched to the set of contacts. The set of cavities may form a hollow-core light pipe that may be used for measurements over a range of optical frequencies. As such, a light may be emitted through the set of cavities, where a measurement may be obtained at the interface between the set of contacts and the set of cavities based on the emitted light.

A gas-leak detection system includes a narrow-wavelength tunable laser, a beam scanner, a detector, a plurality of retroreflectors, and signal-processing electronics. The laser, beam scanner, and detector are co-located, and the plural retroreflectors are distributed throughout a facility. The laser is tuned so that its optical frequency is near to a frequency of an absorption line of a gas of interest, and modulated to create a controlled scan across the frequency of the absorption line. The beam scanner guides the laser beam towards some or all of the retroflectors, depending on the system’s operating mode. The retroreflectors return respective beams to the detector, where the respective intensities thereof are detected. The intensity of a return beam correlates to gas concentration. Since gas-concentration data is obtained at multiple locations, a gas leak and its location may be determined.

This communication control system is for controlling optical wireless communication between rack-mounted servers stored in server racks and comprises: a reception unit for receiving designation of servers that perform communication with each other; a specifying unit for specifying whether the server racks in which the servers performing communication with each other are stored are the same server rack or different server racks on the basis of information that is stored in a storage unit and pertains to the server racks in which a plurality of servers stored in individual server racks are stored and the positions at which the servers are stored in the server racks; and a setting unit that sets a first optical frequency for use in communication between servers stored in the same server rack and a second optical frequency for use in communication between servers stored in different server racks, (1) sets first optical frequencies that are different from each other and not near each other when optical wireless communication between two or more sets of different servers occurs in the same server rack, (2) sets second optical frequencies that are different from each other and not near each other when optical wireless communication between two or more different sets of servers occurs between servers stored in different server racks, and (3) sets an optical frequency that does not overlap with the first optical frequencies and the second optical frequencies.

An apparatus for processing data associated with an optical fiber, the apparatus comprising at least one processor, and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to: perform a plurality of measurements applying a distributed acoustic sensing technique to the optical fiber to obtain a plurality of measurement signals, each of the plurality of measurements using a different optical frequency and a single spatial fiber mode of the optical fiber, determine at least one measurand of a plurality of measurands associated with the optical fiber based on the plurality of measurement signals.

A control unit (24-1) stabilizes the frequency of a carrier envelope offset signal of an optical frequency comb. A control unit (24-2) stabilizes the frequency intervals of optical frequency comb modes in each of four operations having different mode frequency intervals. A detecting unit (34) detects the frequency of a beat signal generated by interference between light being measured from a light source (21) being measured and the optical frequency comb. An optical frequency calculating unit (30) calculates first to fourth order approximate values of the mode number in the first operation on the basis of the frequency intervals in each of the four operations and the frequency of the beat signal, calculates a true mode number in the first operation on the basis of the approximate values, and calculates the frequency of the light being measured.

The present invention relates to a second-order nonlinear optical crystal of formamidine thiosulfate, and its preparation and application. The crystal material has a chemical formula of [CH(NH2)2]2SO3S, a molecular weight of 203.27, belongs to the orthorhombic crystal system, has a space group of P212121, unit cell parameters of α=β=γ=90°, Z=4, and a unit cell volume of . The formamidine thiosulfate crystal material of the present invention has excellent optical properties. Under 1064nm laser irradiation, the powder frequency harmonic intensity is approximately twice that of potassium dihydrogen phosphate crystal, and phase matching can be achieved. In addition, the crystal material has a wide light transmission band, an ultraviolet absorption cutoff edge of 253nm, an optical band gap of 4.90eV, and is easy to grow. Optical frequency conversion technologies such as second harmonic generation and optical parametric amplification can be used to expand the wavelength range of coherent light sources. Therefore, the crystal material has important application value in fields such as laser frequency conversion and optoelectronic information storage.

The invention discloses a measurement type picometer-level displacement resolution generation method based on twin double cavities, and the method comprises the steps: employing a group of twin Fabry-Perot cavities with matched parameters, and the twin Fabry-Perot cavities comprise a measurement cavity and a reference cavity; based on the PDH technology, the lasers of the two lasers are locked to harmonic peaks of the measuring cavity and the reference cavity respectively, and then the resonant frequency is measured through an optical frequency comb to represent the displacement amount; a set frequency stepping signal is output through an optical phase-locked loop, the frequency stepping signal is converted into a voltage control signal to be loaded to a PZT of a measurement cavity, the PZT is driven to drive a reflector to move so as to change the cavity length, and a controllable picometer-scale standard displacement step is generated. According to the invention, on the basis of twin Fabry-Perot cavity resonant frequency differential mode detection, a common mode signal caused by Fabry-Perot cavity environment noise can be suppressed, the cavity length displacement is directly traced to an optical frequency standard, and absolute traceability and high-resolution measurement of a picometer-level displacement signal are realized.