The Experts below are selected from a list of 49359 Experts worldwide ranked by ideXlab platform
Anbo Wang - One of the best experts on this subject based on the ideXlab platform.
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toward eliminating signal demodulation jumps in optical fiber intrinsic fabry perot interferometric sensors
2011Co-Authors: Evan M Lally, Anbo WangAbstract:Fiber optic Fabry-Perot sensors are commonly interrogated by spectral interferometric measurement of optical Path Difference (OPD). Spurious jumps in sensor output, previously attributed to noise, are often observed in OPD-based measurements. Through analysis and experimentation based on intrinsic Fabry-Perot interferometric (IFPI) sensors, we show that these discontinuities are actually caused by a time-varying interferogram phase term. We identify several physical causes for varying initial phase and derive a threshold value at which it begins to cause errors in the sensor output. Finally, we present a total phase measurement method as an alternative to OPD-based techniques to reduce the occurrence of output signal jumps.
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grating assisted operating point tuning for fiber optic fabry perot interferometric sensors
2004Co-Authors: Bing Yu, Gary R. Pickrell, Anbo WangAbstract:A grating-assisted operating-point tuning system was designed to dynamically stabilize the operating-point of a fiber Fabry-Perot interferometric sensor to compensate for manufacturing errors and environment perturbation induced drifts. The system uses a diffraction grating and a feedback control, functioning as a tunable bandpass optical filter, and can be used as an effective demodulation subsystem in sensor systems based on optical interferometers using a broadband light source. This demodulation method features unlimited signal detection bandwidth, high tuning speed, large tunable range, increased interference fringe contrast, and a potential of absolute optical Path Difference measurement. Sensitivity improvements were demonstrated with a fiber Fabry-Perot acoustic wave sensor system.
Philippe Grangier - One of the best experts on this subject based on the ideXlab platform.
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observation of anticorrelated modal noise in a quasi single mode laser diode with a michelson interferometer
1997Co-Authors: Jean-philippe Poizat, Philippe GrangierAbstract:The light emitted by a quasi-single-mode free-running laser diode is sent through a Michelson interferometer, and the intensity noise of the outgoing light is studied with respect to the Path Difference between the two arms of the interferometer. The level of this noise is determined by very strong anticorrelations between the main mode and the many very weak, but noisy, longitudinal side modes. The different interference patterns of these various modes can modify the noise compensation effect, leading to a large excess noise. Phase-noise effects also come into the picture, since a Michelson interferometer tuned around a nonzero Path Difference is a dispersive element capable of converting phase noise into intensity noise. The observed data is in good agreement with a phenomenological model that attributes phase noise and correlated intensity noises to all the modes. The parameters of this model can be inferred from the experimental data.
Jianlin Zhao - One of the best experts on this subject based on the ideXlab platform.
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quantitative measurement of thermal lensing in diode side pumped nd yag laser by use of digital holographic interferometry
2016Co-Authors: Zhaomin Wang, Chee Yuen Cheng, Jianlin ZhaoAbstract:Thermal lensing in diode-side-pumped Nd:YAG laser has been measured quantitatively using digital holographic interferometry. A series of holograms, carrying the information of the laser rod under different pump currents, are recorded with a CCD and reconstructed numerically. The optical Path Difference induced by the thermal lensing and the corresponding evolution process under different currents are obtained accordingly. Further, the thermal lensing diopters, induced aberrations, and its Zernike coefficients are calculated. The proposed method can be applied in the thermal lensing measurement and the optimization design of a laser resonator.
Evan M Lally - One of the best experts on this subject based on the ideXlab platform.
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toward eliminating signal demodulation jumps in optical fiber intrinsic fabry perot interferometric sensors
2011Co-Authors: Evan M Lally, Anbo WangAbstract:Fiber optic Fabry-Perot sensors are commonly interrogated by spectral interferometric measurement of optical Path Difference (OPD). Spurious jumps in sensor output, previously attributed to noise, are often observed in OPD-based measurements. Through analysis and experimentation based on intrinsic Fabry-Perot interferometric (IFPI) sensors, we show that these discontinuities are actually caused by a time-varying interferogram phase term. We identify several physical causes for varying initial phase and derive a threshold value at which it begins to cause errors in the sensor output. Finally, we present a total phase measurement method as an alternative to OPD-based techniques to reduce the occurrence of output signal jumps.
Wei Peng - One of the best experts on this subject based on the ideXlab platform.
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rhombic optical Path Difference bias white light interferometric fiber optic gyroscope
2021Co-Authors: Zhenguo Jing, Qiang Liu, Yueying Liu, Yang Cheung, Zhiyuan Huang, Dapeng Zhou, Wei PengAbstract:We present a novel, to the best of our knowledge, white light interferometric fiber-optic gyroscope (IFOG) scheme using a fiber-optic rhombic optical Path Difference (OPD) bias structure to interrogate with a sensing coil to realize rotation rate measurement without a phase modulator. The OPD bias structure composed of four (2×1) 3 dB single-mode fiber couplers was constructed to implement non-reciprocal OPD bias. White light interferometric demodulation was utilized to acquire the change in OPD due to the Sagnac-phase shift. Absolute linear output can be obtained. We produced the principle prototype of rhombic OPD bias white light IFOG without utilizing a phase modulator. An experimental demonstration of the IFOG prototype system achieves linear output with respect to the OPD Difference in detecting rotation rate.
