13 results about "Fiber optic interferometer" patented technology

The present invention discloses an ultra-fine diameter heterogeneous fiber optic hydrophone and its manufacturing process. The hydrophone includes a core shaft, a sensitizing cylindrical shell, and a heterogeneous fiber optic interferometer. A cavity is disposed through the core shaft. Sensitizing cylindrical shells are symmetrically arranged on both sides of the core shaft. A heterogeneous fiber optic interferometer is installed in the cavity of the core shaft. The heterogeneous fiber optic interferometer includes a heterogeneous fiber optic coupler, a reference arm ultra-short fine diameter fiber, and a sensing arm ultra-fine diameter fiber. The heterogeneous fiber optic coupler, the reference arm ultra-short fine diameter fiber, and the reference arm mirror are fixedly arranged flatly in the cavity. The sensing arm ultra-fine diameter fiber is evenly wound around the sensitizing cylindrical shell and its end is connected to a sensing arm mirror. The present invention uses ultra-fine diameter ultra-small mode field fibers and fine diameter small mode field fibers to form a heterogeneous fiber optic interference structure, and the fiber is coiled and packaged in an ultra-fine high-sensitivity structure, realizing the fabrication of an ultra-fine diameter, low optical insertion loss, and high-sensitivity hydrophone, which can be applied to fields such as underwater acoustic target detection, environmental noise measurement, and undersea mineral resource exploration.

This invention relates to the field of geostress measurement, specifically to a geostress monitoring instrument for soft rock areas based on fiber optic technology. The instrument includes: a cylindrical outer shell with a first through-hole along its length, the outer shell having a uniform thickness throughout; a central column positioned along the center of the first through-hole; a base; a top cover; a thermometer mounted on the central column; an azimuth gauge mounted on the central column; a fiber optic sensor tray mounted on the central column; a fiber optic interferometer probe mounted on the fiber optic sensor tray; and a fiber optic cable, one end of which passes through the inner side of the central column and connects to the azimuth gauge, thermometer, and fiber optic interferometer probe, while the other end is externally connected to an optical signal modem. This invention addresses the problems of existing geostress monitoring instruments, such as large measurement errors, unclear measured physical quantities, short probe lifespan, and difficulty in adapting to complex underground environments.

The application provides a demodulation system and method for simultaneously demodulating displacement and distance in real time, belongs to the field of optical fiber interferometer measurement, and comprises a collection unit for collecting displacement interference signals, distance main interference signals and distance auxiliary interference signals, and a processing unit connected with the collection unit; the processing unit comprises a PL end and a PS end; the PL end is provided with parallel displacement preprocessing modules and distance preprocessing modules; the PS end is provided with parallel displacement calculation modules and distance calculation modules; the displacement preprocessing modules are bidirectionally connected with the displacement calculation modules; and the distance calculation modules are connected with the distance preprocessing modules. The application realizes high-precision measurement functions of high-speed real-time relative displacement and absolute distance in the same system.

The invention provides a built-in cable joint partial discharge monitoring method and device, and the method comprises the steps: enabling an optical fiber sensor for monitoring partial discharge to be connected to an optical fiber interferometer, and monitoring a partial discharge signal of a cable joint in real time; identifying a discharge type according to the partial discharge signal; the optical fiber sensor is arranged between a cold shrink tube and an insulating surface of the cable joint; the optical fiber sensor comprises an optical fiber sensor which winds a sensor optical fiber on a winding sheet. By designing a special optical fiber sensor and arranging the optical fiber sensor between a cold shrink tube and a crosslinked polyethylene insulation surface of the cable joint, real-time monitoring of partial discharge signals of the cable joint is realized.

This invention provides a flexible micro / nano fiber optic multiplexed chip and its monitoring system and method, belonging to the field of biomedical sensing technology. It includes: a myocardial marker detection layer with an embedded array of micro / nano fiber optic interferometers modified with different biological probes for simultaneous detection of multiple cardiovascular disease markers in sweat; a microfluidic channel layer with microfluidic channels for collecting and transmitting sweat and an outlet for sweat excretion; and a pulse wave monitoring layer with an embedded U-shaped micro / nano fiber for real-time pulse wave monitoring based on the bending loss principle, with a localized microfluidic channel inlet for sweat collection. Through the above technical solution, dual-modal multi-information synchronous monitoring is achieved, with high performance and high reliability.

The invention relates to an optical fiber interferometer absolute displacement demodulation system and method based on gas absorption spectrum reference, and the system comprises a laser assembly which comprises a laser device and a first coupler; the detection light path assembly comprises a sensing head, an optical circulator and a first photoelectric detector, the sensing head is used for measuring displacement, the sensing head and the first photoelectric detector are both connected with the optical circulator, and the laser is connected with the optical circulator; the first reference light path assembly comprises a second photoelectric detector, and the laser is connected with the second photoelectric detector; the second reference light path assembly comprises a third photoelectric detector and a gas absorption cell, and the laser, the first coupler, the gas absorption cell and the third photoelectric detector are connected in sequence; and a data processing control assembly. According to the invention, the high-precision absolute displacement is measured remotely by using the optical fiber interferometer referenced by the gas absorption spectrum without being influenced by the wavelength stability, the wavelength modulation efficiency, the initialization phase difference and the like of the laser.

The invention is suitable for the technical field of optical fiber sensing, and relates to a double-interferometer push-pull and common-mode noise differential suppression optical fiber hydrophone, which comprises a first thin-wall cylinder, a second thin-wall cylinder, a first optical fiber interferometer and a second optical fiber interferometer, the first thin-wall cylinder is embedded in the second thin-wall cylinder, a first optical fiber winding area and a second optical fiber winding area are arranged on the first thin-wall cylinder, and a third optical fiber winding area and a fourth optical fiber winding area are arranged on the second thin-wall cylinder; the first optical fiber interferometer comprises a first short-arm sensing optical fiber, a first long-arm sensing optical fiber, a first Faraday rotating mirror and a second Faraday rotating mirror, and the second optical fiber interferometer comprises a second short-arm sensing optical fiber, a second long-arm sensing optical fiber, a third Faraday rotating mirror and a fourth Faraday rotating mirror. According to the invention, the dual-push-pull structure is formed by the dual-fiber interferometer, so that temperature drift noise and optical scattering noise caused by the ultra-long sensing fiber are effectively reduced, and common-mode noise formed by light source vibration, transmission optical cable jitter and the like is effectively suppressed.

The application discloses a fiber-optic gyroscope and a comb pulse error suppression system and method. The fiber-optic gyroscope comprises a wide-spectrum light source, a fiber-optic interferometer, an electro-optic intensity modulator, a photoelectric detector and a signal processing circuit. The wide-spectrum light source is used to provide a wide-spectrum light signal to the fiber-optic interferometer. The fiber-optic interferometer is used to generate at least one light interference signal according to the wide-spectrum light signal and mechanical rotation. The electro-optic intensity modulator is used to suppress the comb pulse of the light interference signal according to at least one modulation signal. The photoelectric detector is used to generate an electric measurement signal according to the light interference signal after suppression. The signal processing circuit is used to modulate the waveform of the wide-spectrum light signal propagating reversely in the fiber-optic interferometer according to the electric measurement signal, and generate the modulation signal according to the electric measurement signal. The signal processing circuit is used to obtain the rotation information of the mechanical rotation according to the electric measurement signal. The embodiment of the application suppresses the influence caused by the comb pulse error from the root by improving the electro-optic intensity modulator and the signal processing circuit, expands the effective sampling interval of the light interference signal, and suppresses the zero-bias error caused by the demodulation of the electric measurement signal.

This invention discloses a parallel cascaded refractive index sensor and a refractive index detection method based on the vernier effect. The device includes: single-mode fiber L1 and single-mode fiber L2, connected in parallel; the polymer coating layer of single-mode fiber L1 is stripped; both single-mode fiber L1 and single-mode fiber L2 have two semi-circular bends, which do not satisfy the total internal reflection condition; the method includes: immersing the upstream bend of single-mode fiber L1 into the liquid to be tested, and acquiring the wavelength shift data of the trough of the spectral line; based on the wavelength shift data, determining the refractive index of the liquid to be tested from a preset wavelength shift-refractive index relationship curve. This invention uses the bending of single-mode fiber to create a refractive index sensor, utilizing the phenomenon that changes in external refractive index cause a shift in the transmission spectral line, and amplifying the shift using the vernier effect principle to construct a fiber optic interferometer sensing structure, thereby achieving the purpose of high-sensitivity measurement of refractive index.

This invention discloses a photodiode response stability evaluation device and method based on a fiber optic interferometer structure, comprising a tunable laser source module, an unbalanced Michelson fiber optic interferometer module, and a data acquisition and processing module. The tunable laser source module provides an adjustable light source. The unbalanced Michelson fiber optic interferometer module enables passive external modulation of the optical signal. The interference optical signals of the reference photodiode and the photodiode under test are detected by a dual-channel transimpedance amplifier and converted into interference voltage signals. The data acquisition and processing module analyzes and demodulates the fluctuation of the phase difference between the two detection signals from the reference photodiode and the photodiode under test, converting the light intensity error caused by the response stability of the photodiode under test into a phase error, obtaining the standard deviation of the phase difference of the dual-channel interference voltage signals, and comparing it with a preset phase detection accuracy to evaluate whether the response stability of the photodiode under test meets the system requirements.

This invention belongs to the field of fiber optic sensing and recognition technology, specifically an object shape recognition system based on machine learning and fiber optic microphone arrays. The system includes a measurement optical path based on a single-core feedback Sagnac fiber optic interferometer, a microphone array sensor composed of multiple fiber optic coils (a component of the optical path), an obstacle movement device, a sound source, and a signal processing unit. By sensing sound signals through the fiber optic microphone array and extracting time-frequency features using a short-time Fourier transform algorithm, combined with a ResNet50 convolutional neural network or a support vector machine (SVM) algorithm, it achieves the recognition of obstacles of different shapes and types in the sound field. This system possesses advantages such as strong anti-electromagnetic interference capability, high sensitivity, low distortion over long distances, small size, and high recognition accuracy.

The invention provides a pressure measuring device and method based on an optical fiber interferometer, and the device comprises a laser, the optical fiber interferometer, a Faraday rotating mirror and a photoelectric detector, the laser emitted by the laser is transmitted to a sensing arm optical fiber, a reference arm optical fiber and the sensing arm optical fiber through an optical fiber coupler in the optical fiber interferometer, and the sensing arm optical fiber is wound on a sensitization transduction structure. When external pressure acts on the sensitization transduction structure, the sensitization transduction structure deforms, the length of the sensing arm optical fiber changes along with the deformation of the sensitization transduction structure, and laser transmitted by the sensing arm optical fiber and the reference arm optical fiber is reflected by the Faraday rotating mirror and then returns to the optical fiber coupler for interference. An optical signal generated by interference is received by a photoelectric detector and is converted into an electric signal for resolving external pressure information.

The present invention provides a pressure measurement device and method based on a fiber optic interferometer, comprising a laser, a fiber optic interferometer, a Faraday rotator, and a photoelectric detector. Laser light emitted by the laser is transmitted to a sensing arm optical fiber and a reference arm optical fiber through a fiber optic coupler in the fiber optic interferometer. The sensing arm optical fiber is wound on a sensitivity-enhancing transducer structure. When external pressure acts on the sensitivity-enhancing transducer structure, the sensitivity-enhancing transducer structure will deform, and the length of the sensing arm optical fiber will change with the deformation of the sensitivity-enhancing transducer structure. The laser light transmitted by the sensing arm optical fiber and the reference arm optical fiber is reflected by the Faraday rotator and then returned to the fiber optic coupler to cause interference. The light signal generated by the interference is received by the photoelectric detector and converted into an electrical signal for calculating external pressure information.