Low-coherence interferometric method for vibration measurement using 3x3 fiber optic coupler

2000 ◽  
Author(s):  
Milos C. Tomic ◽  
Zoran V. Djinovic
Keyword(s):  
Fiber Optic ◽  
Vibration Measurement ◽  
Interferometric Method ◽  
Low Coherence ◽  
Optic Coupler

Novel optical processing scheme for interferometric vibration measurement using a low-coherence source with a fiber optic probe

1991 ◽  
Author(s):  
Kenneth Weir ◽  
William J. O. Boyle ◽  
Andrew W. Palmer ◽  
Kenneth T. V. Grattan ◽  
B. T. Meggitt
Keyword(s):  
Fiber Optic ◽  
Vibration Measurement ◽  
Fiber Optic Probe ◽  
Optical Processing ◽  
Processing Scheme ◽  
Low Coherence ◽  
Optic Probe

scholarly journals Nanometer-Scale Vibration Measurement Using an Optical Quadrature Interferometer Based on 3 × 3 Fiber-Optic Coupler

Sensors ◽  
2020 ◽  
Vol 20 (9) ◽  
pp. 2665 ◽  
Author(s):  
Soongho Park ◽  
Juhyung Lee ◽  
Younggue Kim ◽  
Byeong Ha Lee
Keyword(s):  
Fiber Optic ◽  
Processing Technique ◽  
Vibration Measurement ◽  
Nanometer Scale ◽  
Interference Signal ◽  
Actual System ◽  
Sinusoidal Vibration ◽  
Entire Complex ◽  
Interference Signals ◽  
Optic Coupler

We propose a nanometer-scale displacement or vibration measurement system, using an optical quadrature interferometer and the post-processing technique that extracts the parameters necessary for characterizing the interferometric system. Using a 3 × 3 fiber-optic coupler, the entire complex interference signal could be reconstructed with two interference signals measured at two return ports of the coupler. The intrinsic phase difference between the return ports was utilized to obtain the quadratic part of the interference signal, which allowed one to reconstruct the entire complex interference signal. However, the two measured signals were appreciably affected by the unequal detector gains and non-uniform intrinsic phases of the coupler. Fortunately, we could find that the Lissajous curve plotted by the two signals of the interferometric system would form an ellipse. Therefore, by fitting the measured Lissajous curve to an ellipse, we could extract the parameters characterizing the actual system, which allowed the nanometer-scale measurement. Experimental results showed that a 20 kHz sinusoidal vibration with an amplitude of 1.5 nm could be measured with a standard deviation of 0.4 nm.

scholarly journals Pendulum-Type Hetero-Core Fiber Optic Accelerometer for Low-Frequency Vibration Monitoring

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2528 ◽  
Author(s):  
Hiroshi Yamazaki ◽  
Ichiro Kurose ◽  
Michiko Nishiyama ◽  
Kazuhiro Watanabe
Keyword(s):  
Fiber Optics ◽  
Electromagnetic Interference ◽  
Large Scale ◽  
Fiber Optic ◽  
Low Frequency ◽  
Fiber Optic Sensor ◽  
Vibration Monitoring ◽  
Vibration Measurement ◽  
Displacement Sensor ◽  
Core Fiber

In this paper, a novel pendulum-type accelerometer based on hetero-core fiber optics has been proposed for structural health monitoring targeting large-scale civil infrastructures. Vibration measurement is a non-destructive method for diagnosing the failure of structures by assessing natural frequencies and other vibration patterns. The hetero-core fiber optic sensor utilized in the proposed accelerometer can serve as a displacement sensor with robustness to temperature changes, in addition to immunity to electromagnetic interference and chemical corrosions. Thus, the hetero-core sensor inside the accelerometer measures applied acceleration by detecting the rotation of an internal pendulum. A series of experiments showed that the hetero-core fiber sensor linearly responded to the rotation angle of the pendulum ranging within (−6°, 4°), and furthermore the proposed accelerometer could reproduce the waveform of input vibration in a frequency band of several Hz order.

scholarly journals Digital phase demodulation for low-coherence interferometry-based fiber-optic sensors

2018 ◽  
Vol 411 ◽  
pp. 27-32 ◽  
Author(s):  
Y. Liu ◽  
R. Strum ◽  
D. Stiles ◽  
C. Long ◽  
A. Rakhman ◽  
...  
Keyword(s):  
Fiber Optic ◽  
Fiber Optic Sensors ◽  
Low Coherence ◽  
Digital Phase ◽  
Low Coherence Interferometry ◽  
Phase Demodulation
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