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Your search keyword '"Dang, Fanyang"' showing total 32 results
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32 results on '"Dang, Fanyang"'

6. Distributed Chromatic Dispersion Compensation Method Based on Mismatch Factor for High Resolution OFDR

Author

Zou, Chen, Xie, Dongcheng, Lin, Cuofu, Yu, Zhangjun, Zhu, Yunlong, Zhu, Yao, Dang, Fanyang, Yuan, Yonggui, Yang, Jun, Wang, Yuncai, and Qin, Yuwen

Abstract

Optical frequency domain reflectometry (OFDR) can provide a powerful tool for fiber components and devices diagnosis and characterization. However, apart from laser source phase noise, the impact of the chromatic dispersion effect on the system is severely increased with the measurement length and laser tunable range. We propose a distributed chromatic dispersion compensation method for the device under the test (DUT) with complex structures containing different dispersive media connections in OFDR. Based on the mismatch factor (which is related to the difference in dispersion coefficient between the reference fiber and DUT), chromatic dispersion errors in the signal from different dispersion mediums can be compensated segment by segment by constructing the dispersion phase error signal. The compensation method is evaluated by experiments on DUT with multiple material dispersion (including reduced-cladding single-mode fiber (RC SMF) and dispersion compensation fiber (DCF)) and various measurement distances. Finally, we experimentally analyzed the internal reflection of a multifunctional integrated optical chip (MFIOC). Sweeping the laser source by 160 nm, the input coupling, output coupling, beam splitting, and defect points are individually revealed with a high resolution better than 15 $\mu$m. We believe that this approach enables high-precision quantitative measurements as well as accurate identification and localization of fault diagnosis for optical fibers and devices.

Published
2024
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15. Distributed Polarization Measurement for Fiber Sensing Coils: A Review

Author

Yu Zhangjun, Dang Fanyang, Jun Yang, Zhang Xiang, Yuncai Wang, Yonggui Yuan, Yuwen Qin, Lin Cuofu, and Libo Yuan

Subjects
White light interferometry, Optical fiber, Materials science, law, Dynamic range, Electromagnetic coil, Acoustics, Frequency domain, Polarization-maintaining optical fiber, Time domain, Spatial frequency, Atomic and Molecular Physics, and Optics, law.invention
Abstract

Distributed polarization measurement is a significant way to evaluate polarization-maintaining fiber. It can assess the fiber's polarization preserving ability and locate internal defects and external perturbations of a long-distance PM fiber. Distributed polarization crosstalk of a fiber-optic polarization device accurately describes its time-dependent optical performance. Therefore, distributed polarization measurement technology can be used to predict and prevent the performance degradation and failure. However, the remaining shortcomings of existing measurement methods are low dynamic range, short measurement length, inadequate spatial resolution, and low diagnostic ability. This paper reviews recent advances in solving the above issues and presents ways to obtain high performances: a dynamic range > 90 dB, a measurement length > 10 km, a full range spatial resolution < 10 cm, and developments in time domain, frequency domain, and time-frequency domain diagnosis methods. All these high-performance techniques have led to more effective diagnosis of fiber optic sensing coils. This can be demonstrated by a series of comparative measurements and analysis of three PM fiber optic sensing coils in various configurations such as a randomly-wound spool of fiber and a free-standing coil quadrupole-pattern-wound from it, a second coil with and without a flange at various temperatures, and a third coil spliced to a Y waveguide. Each is one of the key configurations during the production processes or the application of the fiber sensing coil. The technical progress reviewed here will greatly promote the development, production, and application of fiber sensing coils.

Published
2021

24. Influence of thickness of hemispherical dome on aerodynamic thermal radiation

Author

Fan Zhi-gang, Ming Yue, Wang Hui, Zhang Rongda, and Dang Fanyang

Subjects
Materials science, Infrared, business.industry, Detector, Aerospace Engineering, Aerodynamics, Radiation, Stagnation point, Atomic and Molecular Physics, and Optics, Dome (geology), Optics, Space and Planetary Science, Thermal radiation, Thermal, Electrical and Electronic Engineering, business
Abstract

Aerodynamically heated high temperature dome will produce strong infrared radiation. In some serious cases when the probe reaches saturation, the detecting precision of the seeker for target can be severely affected. In order to reduce the aerodynamic thermal radiation of the dome, a mathematical model of aerodynamic thermal radiation was developed. The aerodynamic heat and the aerodynamic thermal radiation of the hemispherical dome with different thickness were simulated numerically by software of finite element analysis and the mathematical model of aerodynamic thermal radiation. The influence of the thickness of hemispherical dome on the aerodynamic thermal response and aerodynamic heat radiation was analyzed and obtained. Research indicates that in the same flight conditions and in 10 s, when the thickness of hemispherical dome increases from 3 mm to 8 mm, the stagnation point temperature of the dome reduces by 16.41%; the thermal deformation of the dome reduces by 54.2%; the maximum irradiance of receiving surface of the detector decreases by 84.43%. Therefore increasing the thickness of the dome can not only reduce the temperature of the dome, but also effectively reduce the thermal deformation of the dome and the interference radiation illumination received on the detector.

Published
2018

30. Design on Surface Shape of Conicoidal Conformal Optical Domes

Author

范志刚 Fan Zhigang, 汪东生 Wang Dongsheng, 陈守谦 Chen Shouqian, 张旺 Zhang Wang, 秦兰琦 Qin Lanqi, and 党凡阳 Dang Fanyang

Subjects
Physics, Optics, business.industry, Conformal map, business, Surface shape, Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials
Published
2014

31. Suppression of wavelength-dependent polarization fading using hybrid-polarization scheme in OFDR.

Author

Mou T, Zhu Y, Lin C, Zou C, Xie D, Zhu Y, Dang F, Yuan Y, Gao F, and Yang J

Abstract

What we believe to be a new hybrid-polarization diversity scheme which can eliminate the polarization state variation caused by wavelength tuning of laser in optical frequency domain reflectometry is proposed in the paper. In the scheme, a 45° polarizer is used to maintain the polarization of signals. It decreases the polarization angle fluctuation to 2.81° and realizes a -145 dB test sensitivity with a 32 dB Rayleigh scattering signal-to-noise ratio in a 10 m fiber single test. The polarization fading suppression is achieved for tests with a large wavelength tuning range from 1480 nm to 1640 nm. Meanwhile, a 6 µm spatial resolution is also achieved. The proposed scheme can be applied to the structure measurement of high-precision optical fiber devices with high spatial resolution and sensitivity.

Published
2024
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32. Beyond a 10 7 range-resolution -1 product in an OFDR based on a periodic phase noise estimation method.

Author

Zou C, Lin C, Mou T, Yu Z, Zhu Y, Zhu Y, Dang F, Yuan Y, Yang J, Wang Y, and Qin Y

Abstract

We present and demonstrate a method based on a periodic phase noise estimation in an optical frequency domain reflectometry (OFDR) capable of a beyond 10 7 range-resolution -1 product (RRP) for the first time, which corresponds to 2.5 × improvement compared with the state-of-the-art. The moving average filter is employed to suppress the amplification of noise in the derivation process. Further, with the help of a third-order Taylor expansion, this method provides a highly precise estimation of periodic phase noise, which is the main factor impacting the performance of OFDR systems with medium-to-long measurement range combined with a submillimeter spatial resolution. A spatial resolution within 535 μ m over the measurement range of 8 km is obtained. The proposed method offers a promising technique for fiber network monitoring and sensing applications.

Published
2022
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