Author Affiliations
Abstract
1 Institute of Optics, Department of Physics, Zhejiang University, Hangzhou 310027, China
2 Center for Optics and Optoelectronics Research, College of Science, Zhejiang University of Technology, Hangzhou 310014, China
For most atom interferometers, the vibration isolation unit is applied to reduce vibration noise. In our experiment, instead of isolation, the vibration signals are monitored, and combining with the sensitive function, the compensation phase shift for the atom interferometer is obtained. We focus on the correction over a wide spectrum rather than on “monochromatic” frequencies. The sensitivity of the atom gravimeter can be upgraded by a factor of more than two. Furthermore, we demonstrate that the atom interferometer can still produce a good measurement result without passive vibration isolation in extremely noisy environments by using vibration compensation.
020.3320 Laser cooling 000.2780 Gravity 270.5570 Quantum detectors Chinese Optics Letters
2019, 17(7): 070201
Author Affiliations
Abstract
1 School of Information Science and Engineering and Shandong Provincial Key Laboratory of Laser Technology and Application, Shandong University, Jinan, 250100, China
2 Institute of Automation Shandong Academy of Sciences, Jinan Shandong 250014，China
The improvement of the signal to noise ratio (SNR) has significant meaning to the fiber Bragg grating (FBG) sensing system. The source of the noise as well as the signal attenuation of the FBG sensing system is analyzed. It is found that optical noise caused by the optical return loss (ORL) is the main source of noises in the system, and the coupler is the main source of attenuation of the signal. The cause of the ORL in fiber-optic elements (such as jumper cables connector and fiber end) is presented. In addition, suggestions to optimize the fiber optical sensing network in order to improve the SNR are presented. Methods to suppress noises caused by the fiber end interfaces of FBGs, including using index-matching fluid, bending fiber pigtails in the way mentioned in this paper and cleaving the slant angle of the fiber interfaces to be 8°, all contribute to the optimized SNR. Besides, the thermo-weld method is suggested to be used for both parallel and serial FBG setups to provide a low insertion loss. The results would be a useful engineering tool to design the high SNR optical sensing system.
SNR return noise return loss fiber Bragg grating reflection of fiber end interface bending loss Photonic Sensors
2012, 2(2): 148
Author Affiliations
Abstract
1 School of Information Science and Engineering and Shandong Provincial Key Laboratory of Laser Technology and Application, Shandong University, Jinan, 250100, China
2 School of Shandong Provincial Party Committee of Communist Party of China, Jinan, 250021, China
Scanning the absorption spectral line of water vapor through wavelength around 1368.597nm is successfully used to measure the value of micro-moisture content. The synchronous superposition average of original signal algorithm based on labview is innovated and applied to detecting weak spectrum absorption signal instead of low pass filter. Two data processing methods are used to get the concentration of water vapor in ppm: one is a general formula method which has newly deduced a general formula to calculate the concentration of gas with temperature and beam intensity ratio when the pressure is equal to or greater than 1atm; the other is engineering calibration method which is proved to have high resolution and accuracy with the fitted curve of beam intensity ratio and concentration in ppm when the temperature changes form 258K to 305K and the pressure ranges from 1atm to 5 atm.
Water-vapor detection scanning spectra detecting under high gas pressure near-infrared absorption measurement technology ha Photonic Sensors
2012, 2(1): 71
