Stimulated Brillouin scattering-induced phase noise is harmful to interferometric fiber sensing systems. The localized fluctuating model is used to study the intensity noise caused by the stimulated Brillouin scatteri...Stimulated Brillouin scattering-induced phase noise is harmful to interferometric fiber sensing systems. The localized fluctuating model is used to study the intensity noise caused by the stimulated Brillouin scattering in a single-mode fiber. The phase noise structure is analyzed for an interferometric fiber sensing system, and an unbalanced Michelson interferometer with an optical path difference of 1 m, as well as the phase-generated carrier technique, is used to measure the phase noise. It is found that the phase noise is small when the input power is below the stimulated Brillouin scattering threshold, increases dramatically at first and then gradually becomes flat when the input power is above the threshold, which is similar to the variation in relative intensity noise. It can be inferred that the increase in phase noise is mainly due to the broadening of the laser linewidth caused by stimulated Brillouin scattering, which is verified through linewidth measurements in the absence and presence of the stimulated Brillouin scattering.展开更多
A simple model is developed to study the mechanism of stimulated Brillouin scattering（SBS） suppression with frequency-modulated laser in optical fiber. By taking into account the laser frequency distribution along t...A simple model is developed to study the mechanism of stimulated Brillouin scattering（SBS） suppression with frequency-modulated laser in optical fiber. By taking into account the laser frequency distribution along the fiber induced by frequency modulation, the average effective Brillouin gain is calculated to determine the SBS threshold. Experimental results show agreement with the numerical analysis. The application for SBS suppression in interferometric fiber sensing system is also discussed in this paper. The results show that the maximum input power can be increased effectively by frequency modulation method.展开更多
Optical fiber interferometric sensors are of great importance in chemistry,biology,and medicine disciplines owing to high-sensitivity and high-quality factor.However,due to the limitation of free spectral range,the in...Optical fiber interferometric sensors are of great importance in chemistry,biology,and medicine disciplines owing to high-sensitivity and high-quality factor.However,due to the limitation of free spectral range,the inherent trade-off between wide measurement range and high sensitivity poses a persistent challenge in interference sensor development,which has fundamentally hindered their widespread adoption in precision measurement applications.In this work,a long short-term memory neural network is utilized in a Mach-Zehnder interference-based refractive index sensor to break the free spectral range limitation.Unique gating mechanism in long short-term memory neural network enables it to efficiently process long-term dependent sequence information,such as interference spectrum,avoiding the need for complex spectral signal analysis.A one-to-one mapping relationship is established between the interference spectrum and refractive index with root mean square error of 3.029×10^(−4)and a coefficient of determination of 0.99971.The measurement range is extended from a single free spectral range of 1.3333–1.3561 to approximately three free spectral ranges of 1.3333–1.3921 without sacrificing sensitivity.Moreover,a wider measurement range can be achieved with sufficient training data.This work successfully resolves the inherent contradiction between high sensitivity and wide dynamic measurement range in optical interference-based sensors,opening up a path for the next generation of intelligent sensing systems.展开更多
We presented an interferometric phase shift fiber Bragg grating （FBG） sensor, which inherited the advantages of FBG sensors, and, at the same time, the greatly reduced full-width-at-half-maximum bandwidth brought lo...We presented an interferometric phase shift fiber Bragg grating （FBG） sensor, which inherited the advantages of FBG sensors, and, at the same time, the greatly reduced full-width-at-half-maximum bandwidth brought longer coherent length, higher sensitivity, and lower phase noise. Experiments show that at least a 7 dB reduction of phase noise can be achieved compared to FBG sensors interrogated by interferometer with the same optical path difference.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No. 61177073)the Open Fund of Key Laboratory of Optoelectronic Information and Sensing Technologies of Guangdong Higher Education Institutes, Jinan University, China (Grant No. gdol201101)+1 种基金the Fund of Innovation of Graduate School of NUDT, China (Grant No. B110703)Hunan Provincial Innovation Foundation for Postgraduate,China (Grant No. CX2011B033)
文摘Stimulated Brillouin scattering-induced phase noise is harmful to interferometric fiber sensing systems. The localized fluctuating model is used to study the intensity noise caused by the stimulated Brillouin scattering in a single-mode fiber. The phase noise structure is analyzed for an interferometric fiber sensing system, and an unbalanced Michelson interferometer with an optical path difference of 1 m, as well as the phase-generated carrier technique, is used to measure the phase noise. It is found that the phase noise is small when the input power is below the stimulated Brillouin scattering threshold, increases dramatically at first and then gradually becomes flat when the input power is above the threshold, which is similar to the variation in relative intensity noise. It can be inferred that the increase in phase noise is mainly due to the broadening of the laser linewidth caused by stimulated Brillouin scattering, which is verified through linewidth measurements in the absence and presence of the stimulated Brillouin scattering.
基金Project supported by the National Natural Science Foudation of China(Grant No.6177073)
文摘A simple model is developed to study the mechanism of stimulated Brillouin scattering（SBS） suppression with frequency-modulated laser in optical fiber. By taking into account the laser frequency distribution along the fiber induced by frequency modulation, the average effective Brillouin gain is calculated to determine the SBS threshold. Experimental results show agreement with the numerical analysis. The application for SBS suppression in interferometric fiber sensing system is also discussed in this paper. The results show that the maximum input power can be increased effectively by frequency modulation method.
基金supported by the National Natural Science Foundation of China(Grant No.12074331)Natural Science Foundation of Hebei Province of China(Grant No.F2021203112)Open project of Hebei Key Laboratory of Advanced Laser Technology and Equipment(Grant No.HBKL-ALTE2025006).
文摘Optical fiber interferometric sensors are of great importance in chemistry,biology,and medicine disciplines owing to high-sensitivity and high-quality factor.However,due to the limitation of free spectral range,the inherent trade-off between wide measurement range and high sensitivity poses a persistent challenge in interference sensor development,which has fundamentally hindered their widespread adoption in precision measurement applications.In this work,a long short-term memory neural network is utilized in a Mach-Zehnder interference-based refractive index sensor to break the free spectral range limitation.Unique gating mechanism in long short-term memory neural network enables it to efficiently process long-term dependent sequence information,such as interference spectrum,avoiding the need for complex spectral signal analysis.A one-to-one mapping relationship is established between the interference spectrum and refractive index with root mean square error of 3.029×10^(−4)and a coefficient of determination of 0.99971.The measurement range is extended from a single free spectral range of 1.3333–1.3561 to approximately three free spectral ranges of 1.3333–1.3921 without sacrificing sensitivity.Moreover,a wider measurement range can be achieved with sufficient training data.This work successfully resolves the inherent contradiction between high sensitivity and wide dynamic measurement range in optical interference-based sensors,opening up a path for the next generation of intelligent sensing systems.
基金supported by the National Natural Science Foundation of China(No.11574397)the Research Plan of National University of Defense Technology(No.ZK16-03-56)
文摘We presented an interferometric phase shift fiber Bragg grating （FBG） sensor, which inherited the advantages of FBG sensors, and, at the same time, the greatly reduced full-width-at-half-maximum bandwidth brought longer coherent length, higher sensitivity, and lower phase noise. Experiments show that at least a 7 dB reduction of phase noise can be achieved compared to FBG sensors interrogated by interferometer with the same optical path difference.
