A fiber-optical intrusion alarm system based on quasi-distributed fiber Bragg grating （FBG） sensors is demonstrated in this paper. The algorithms of empirical mode decomposition （EMD） and wavelet packet characteri...A fiber-optical intrusion alarm system based on quasi-distributed fiber Bragg grating （FBG） sensors is demonstrated in this paper. The algorithms of empirical mode decomposition （EMD） and wavelet packet characteristic entropy are adopted to determine the intrusion location. The intrusion alarm software based on the Labview is developed, and it is also proved by the experiments. The results show that such a fiber-optical intrusion alarm system can offer the automatic intrusion alarm in real-time.展开更多
A novel fiber Bragg grating （FBG） sensor array system based on digital phase generated carrier （PGC） demodulation and reference compensation method is proposed and set up. Experimental results confirm that the dig...A novel fiber Bragg grating （FBG） sensor array system based on digital phase generated carrier （PGC） demodulation and reference compensation method is proposed and set up. Experimental results confirm that the digital PGC demodulation can be used for wavelength-division-multiplexed FBG sensor array and the reference compensation method can reduce the environmental interference by approximately 40 dB in the frequency range from 20 Hz to 2 kHz. The minimum detectable wavelength-shift of the sensor system is 1 × 10^-3 pm/Hz^1/2.展开更多
A method to interrogate fiber Bragg grating vibration sensor by narrow line width light is demonstrated. The interrogation scheme takes advantage of the intensity modulation of narrow spectral bandwidth light, such as...A method to interrogate fiber Bragg grating vibration sensor by narrow line width light is demonstrated. The interrogation scheme takes advantage of the intensity modulation of narrow spectral bandwidth light, such as distributed feedback laser, when a reflection or transmission spectrum curve of an fiber Bragg grating （FBG） moves due to the strain which is applied on the sensor. The sensor＇s response to accelerating frequency and amplitude is measured by experiment. The factors which have impacts on the sensitivity of the interrogation system are also discussed.展开更多
Magneto-optic fiber Bragg gratings （MFBG） based on magneto-optic materials have a lot of potential applications for sensing and optical signal processing. The transmission and reflection spectra of guided optical wa...Magneto-optic fiber Bragg gratings （MFBG） based on magneto-optic materials have a lot of potential applications for sensing and optical signal processing. The transmission and reflection spectra of guided optical waves in the MFBG are investigated. According to the sensitivity of MFBG spectral lines to the magneto-optic coupling intensity varying with applied magnetic field, a novel magnetic field sensor of high-resolution up to 0.01 nm/（kA/m） is predicted.展开更多
Recent progress in long-distance in-Fiber Bragg Grating （FBG） sensor systems at University of Electronic Science ＆ Technology of China （UESTC） is reviewed in this paper. Two novel approaches with a 50km transmiss...Recent progress in long-distance in-Fiber Bragg Grating （FBG） sensor systems at University of Electronic Science ＆ Technology of China （UESTC） is reviewed in this paper. Two novel approaches with a 50km transmission distance are proposed and demonstrated. The first one is based on the combination of bidirectional Raman amplification and a dual Erbium-Doped Fiber （EDF） configuration. A good Signal-to-Noise Ratio （SNR） of ～16dB is achieved with only a pump power of ～280 mW, which is ～10 dB higher than that without amplification. The second is based on a novel tunable fiber ring laser configuration with hybrid Raman/EDFA configuration. Experimental results show that an excellent optical SNR of-～60 dB has been achieved for a 50 km transmission distance with a low Raman pump power of ～170 mW and a low EDFA pump power of～40 mW at wavelength of 980 nm. It is anticipated that these long-distance FBG sensing systems could find important applications in health monitoring of large infra-structures, such as oil or gas pipelines, ultra-long bridges and tunnels, river banks, and so on.展开更多
基金supported by the National Natural Science Foundation of China under Grant No. 60537040.
文摘A fiber-optical intrusion alarm system based on quasi-distributed fiber Bragg grating （FBG） sensors is demonstrated in this paper. The algorithms of empirical mode decomposition （EMD） and wavelet packet characteristic entropy are adopted to determine the intrusion location. The intrusion alarm software based on the Labview is developed, and it is also proved by the experiments. The results show that such a fiber-optical intrusion alarm system can offer the automatic intrusion alarm in real-time.
基金supported by the National 863 Program under Grant No. 2007AA03Z415.
文摘A novel fiber Bragg grating （FBG） sensor array system based on digital phase generated carrier （PGC） demodulation and reference compensation method is proposed and set up. Experimental results confirm that the digital PGC demodulation can be used for wavelength-division-multiplexed FBG sensor array and the reference compensation method can reduce the environmental interference by approximately 40 dB in the frequency range from 20 Hz to 2 kHz. The minimum detectable wavelength-shift of the sensor system is 1 × 10^-3 pm/Hz^1/2.
基金supported by the 11th Five Years Key Programs for Science and Technology Development of China under Grant No. 2006BAK04B02Natural Science Foundation of Shandong Province under Grant No. 2006ZRC01022.
文摘A method to interrogate fiber Bragg grating vibration sensor by narrow line width light is demonstrated. The interrogation scheme takes advantage of the intensity modulation of narrow spectral bandwidth light, such as distributed feedback laser, when a reflection or transmission spectrum curve of an fiber Bragg grating （FBG） moves due to the strain which is applied on the sensor. The sensor＇s response to accelerating frequency and amplitude is measured by experiment. The factors which have impacts on the sensitivity of the interrogation system are also discussed.
基金supported by the National Natural Science Foundation of China under Grant No. 60671027the Application Basis Research Foundation of Sichuan Province under Grant No. 07JY029-089.
文摘Magneto-optic fiber Bragg gratings （MFBG） based on magneto-optic materials have a lot of potential applications for sensing and optical signal processing. The transmission and reflection spectra of guided optical waves in the MFBG are investigated. According to the sensitivity of MFBG spectral lines to the magneto-optic coupling intensity varying with applied magnetic field, a novel magnetic field sensor of high-resolution up to 0.01 nm/（kA/m） is predicted.
基金Supported by the Key Project of National Natural Science Foundation of China (No.60537040)
文摘Recent progress in long-distance in-Fiber Bragg Grating （FBG） sensor systems at University of Electronic Science ＆ Technology of China （UESTC） is reviewed in this paper. Two novel approaches with a 50km transmission distance are proposed and demonstrated. The first one is based on the combination of bidirectional Raman amplification and a dual Erbium-Doped Fiber （EDF） configuration. A good Signal-to-Noise Ratio （SNR） of ～16dB is achieved with only a pump power of ～280 mW, which is ～10 dB higher than that without amplification. The second is based on a novel tunable fiber ring laser configuration with hybrid Raman/EDFA configuration. Experimental results show that an excellent optical SNR of-～60 dB has been achieved for a 50 km transmission distance with a low Raman pump power of ～170 mW and a low EDFA pump power of～40 mW at wavelength of 980 nm. It is anticipated that these long-distance FBG sensing systems could find important applications in health monitoring of large infra-structures, such as oil or gas pipelines, ultra-long bridges and tunnels, river banks, and so on.
