Sensor on the twisted fibers for building construction monitoring

We have proposed and demonstrated in recent years an unique technique to synthesize the two-frequency radiation by manipulating the amplitude and the phase of initial one-frequency lightwave. The output frequencies are symmetrical relatively to suppressed initial one and have strongly equal amplitudes and alternative phases. In this paper the principle of two-frequency radiation synthesis is summarized. The information structure of two-frequency radiation is examined and key aspects of its application are discussed concerning to the theory of precision spectral characterization of resonant structures and theory of quasi-harmonic oscillations and potential noise immunity.

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“…For large amplitude harmonic oscillation on the input of linear narrow-band filter with frequency ω and amplitude b we can use (15) and get…”

Section: Quasi-harmonic Signals and Narrow-band Noise On The Output Omentioning

confidence: 99%

“…Based upon this technique, the synthesis of two frequency symmetrical probing radiation (TFSPR), various photonic sensing of fiber optic structures and optical information-processing applications have been developed [9][10][11][12][13][14][15] .…”

Section: Introductionmentioning

confidence: 99%

Theory of symmetrical two-frequency signals and key aspects of its application

Il'in

Morozov²,

Il'in

2014

SPIE Proceedings

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“…Since then these kinds of sensors were developed and have been used in many fields for measuring displacement, acoustic pressure, temperature, force, structural defects, vibration and for medical applications (Lagakos et al, 1981(Lagakos et al, , 1982Lumholt et al, 1991;Pandey and Yadav, 2007;Efendioglu et al,2009;Garcia et al, 2010;Lau et al, 2013). The development process included the shape and design of the deformer (Morozov et al, 2010) or even using other types of optical fibers like microstructured optical fibers to improve their performance (Borisov et al, 2009). The mathematical models and the design parameters of the fiber-optic microbend sensors are discussed in Lagakos et al (1987).…”

Section: Introductionmentioning

confidence: 99%

Low-cost real-time fiber optic sensor for intrusion detection

Abdallah

Fouad

Ahmed

2021

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Purpose The purpose of this paper is to introduce a novel intensity-modulated fiber optic sensor for real-time intrusion detection using a fiber-optic microbend sensor and an optical time-domain reflectometer (OTDR). Design/methodology/approach The proposed system is tested using different scenarios using person/car as intruders. Experiments are conducted in the lab and in the field. In the beginning, the OTDR trace is obtained and recorded as a reference signal without intrusion events. The second step is to capture the OTDR trace with intrusion events in one or multiple sectors. This measured signal is then compared to the reference signal and processed by matrix laboratory to determine the intruded sector. Information of the intrusion is displayed on an interactive screen implemented by Visual basic. The deformer is designed and implemented using SOLIDWORKS three-dimensional computer aided design Software. Findings The system is tested for intrusions by performing two experiments. The first experiment is performed for both persons (>50 kg) in the lab and cars in an open field with a car moving at 60 km/h using two optical fiber sectors of lengths 200 and 500 m. For test purposes, the deformer length used in the experiment is 2 m. The used signal processing technique in the first experiment has some limitations and its accuracy is 70% after measuring and recording 100 observations. To overcome these limitations, a second experiment with another technique of signal processing is performed. Research limitations/implications The system can perfectly display consecutive intrusions of the sectors, but in case of simultaneous intrusions of different sectors, which is difficult to take place in real situations, there will be the ambiguity of the number of intruders and the intruded sector. This will be addressed in future work. Suitable and stable laser power is required to get a suitable level of backscattered power. Optimization of the deformer is required to enhance the sensitivity and reliability of the sensor. Practical implications The proposed work enables us to benefit from the ease of implementation and the reduced cost of the intensity-modulated fiber optic sensors because it overcomes the constraints that prevent using the intensity-modulated fiber optic sensors for intrusion detection. Originality/value The proposed system is the first time long-range intensity-modulated fiber optic sensor for intrusion detection.

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