8 results about "Fiber optic interferometer" patented technology

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.

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 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.