Søgeresultater - Wenjun Ni

A simple and efficient manufacture method of helical long period fiber grating (HLPFG) in a single-mode fiber (SMF) is designed and verified through experiment. Different from the previous fabricating methods, the SMF is heated by a double-side CO₂ laser beam after being twist...

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Acoustic measurement is the most widely used non-electric method to detect partial discharge (PD) signals by detect the ultrasonic waves arisen from partial discharge. To solve the shortages of low sensitivity and susceptibility to interferences, a gold diaphragm based Fabry-Perot interferometer ult...

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A new optical fiber twist sensor with temperature compensation mechanism is designed and experimentally demonstrated. The main structure of this twist sensor is a torsion perturbation point cascaded with single mode-multimode-single mode (SMS) fiber structure. The experimental results show that the...

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A novel fiber sensor for curvature and acoustic wave measurement, which is based on a thin core ultralong period fiber grating (TC-ULPFG), has been proposed and experimentally demonstrated. By tracking the power variation of different resonant wavelength caused by TC-ULPFG, high curvature sensitivit...

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In this paper, we proposed a phase interrogation method for diaphragm-based interferometric optical fiber acoustic sensor based on the spectral coding process. The information of the sound wave is coded on the optical spectrum of the sensor head by wavelength scanning, which builds a map between tim...

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In this paper, we propose an intensity demodulation based fiber sensor for dual-parameters sensing of acoustic wave and lateral pressure. The sensor consists of a long period fiber grating (LPFG) inserted into a Sagnac interferometer (SI). The LPFG is kept straight and fixed on a polyethylene tereph...

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A phase interrogation method for a fiber-optic acoustic sensor based on a short-cavity extrinsic Fabry–Perot interferometer (EFPI) is proposed with two wavelengths. A multichannel tunable optical filter is employed, which selects out two monochromatic beams from the broadband interference...

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We have proposed and experimentally demonstrated an ultrasensitive fiber-optic temperature sensor based on two cascaded Fabry–Perot interferometers (FPIs). Vernier effect that significantly improves the sensitivity is generated due to the slight cavity length difference of the sensing and...

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A Z-shape fiber structure fabricated by CO₂ laser is proposed here for the simultaneous measurement of axial strain and temperature. The Z-shape structure is fabricated by simply exposing a single mode fiber (SMF) to the focused CO₂ laser that causes the...

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An asymmetrical thin-core long-period fiber grating (ATC-LPFG) cascaded with an inline Mach–Zehnder interferometer (MZI) for dual-parameter sensing has been demonstrated. In addition, bending direction is also determined at the same time. A section of thin-core fiber (TCF) is fusion splic...

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Recent research on nonlinear multimode interference (NL-MMI) based mode-locking method provides a new approach for ultrafast all-fiber lasers. Here, we report on the polarization dynamics of group velocity locked vector solitons (GVLVSs) and noise-like vector pulses (NLVPs) in a graded-index multimo...

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