Optical time domain reflectometer

Barnoski, M. K.; Rourke, M. D.; Jensen, S. M.; Melville, R. T.

doi:10.1364/ao.16.002375

Cited by 290 publications

(127 citation statements)

References 4 publications

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“…Distributed fiber sensors nowadays allow performing different types of measurements at any point along a fiber (strain, temperature, vibration, pressure, etc). Among the distributed sensing techniques, Optical time domain reflectometry (OTDR) was first demonstrated over three decades ago [2,3] and is now a commonly used technique for distributed measurement of losses along the fiber (including the measurement of fiber attenuation, the location of broken points and optical connectors, discontinuities, etc).…”

Section: Introductionmentioning

confidence: 99%

Coherent Noise Reduction in High Visibility Phase-Sensitive Optical Time Domain Reflectometer for Distributed Sensing of Ultrasonic Waves

Martins

Martín‐López

Corredera

et al. 2013

J. Lightwave Technol.

156

112

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Abstract-Phase-sensitive optical time domain reflectometry ( OTDR ) is a simple and effective tool allowing the distributed monitoring of vibrations along single-mode fibers. Up to now, OTDRs have been used mostly for the measurement of sub-kHz vibrations, normally in the context of intrusion sensing. In this work, the authors present an experimental and theoretical description of a high-visibility OTDR and its performance when used for ultrasonic vibration measurements. The use of a semiconductor optical amplifier (SOA) in the setup allows to suppress coherent noise and also to improve the spectral response of the pump pulses. These two advantages greatly decrease the detected intra-band noise thus allowing frequency measurements in the limits set by the time of flight of the light pulses while maintaining the simplicity of the scheme, as no post-processing, extremely high coherence lasers or coherent detection methods are required. The sensor was able to measure vibrations of up to 39.5 kHz with a resolution of 5 m over a range which could go up to 1.25 km. This is the first time to our knowledge that a fully distributed measurement of ultrasonic waves was achieved. The statistical behavior of the system was also described theoretically and characterized experimentally.

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Section: Introductionmentioning

confidence: 99%

Coherent Noise Reduction in High Visibility Phase-Sensitive Optical Time Domain Reflectometer for Distributed Sensing of Ultrasonic Waves

Martins

Martín‐López

Corredera

et al. 2013

J. Lightwave Technol.

156

112

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“…A short light pulse is incident into the optical fiber from one end, and the Rayleigh backscattered optical power is measured with an optical time domain reflectometer (OTDR) at the same end. Before crack formation in the concrete member, the backscattered optical power ( ) r P x can be expressed as [17] …”

Section: Crack Sensing Principlementioning

confidence: 99%

A fiber optic sensor for detecting and monitoring cracks in concrete structures

Bao

Wang

Yao

2010

Sci. China Technol. Sci.

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The formation and propagation of cracks reflect the aging and pathologic changes of concrete structures and may cause problems such as seepage and long-term durability. Crack detection and monitoring is therefore an effective way to evaluate structural health conditions. An important challenge in such a task is that the locations and orientations of cracks in concrete structures are difficult to predict due to material inhomogeneity and complexity. The number of the required conventional electric and electromagnetic sensors to cover all possible cracks may be too large to be practical for a monitoring scheme. In this paper, a fiber optic sensor with distributed crack sensing capability based on optical time domain reflectometry is proposed and its sensing principle is introduced. Experiments are conducted to obtain the optical power loss versus crack opening at different fiber inclination angles, and then a model is developed to quantify it. Finally, an experiment is performed to demonstrate the practical application of the sensor. The test results show that detecting and monitoring cracks with the sensor do not require a-priori knowledge of crack locations and orientations. fiber optic sensor, crack, concrete Citation:Bao T F, Wang J L, Yao Y. A fiber optic sensor for detecting and monitoring cracks in concrete structures.

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“…This proposed intrusion sensor is based on the facts that the SOP is modified when the fiber is subject to external perturbations [9] and that the OTDR [10], used here as the interrogating element, realizes a time averaging operation on the backscattered signal. These two features together lead to a flattening of the signal displayed by the OTDR, starting from the intrusion position.…”

Section: Introductionmentioning

confidence: 99%

Development of an Intrusion Sensor Based on a Polarization-OTDR System

2012

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In this paper, we demonstrate the possibility of using a polarization optical time domain reflectometry (POTDR) system as an intrusion sensor. This system measures the evolution of the state of polarization (SOP) along the fiber length. In the typical application of fence monitoring, an intrusion leads to a modification of the SOP, which appears, after a temporal averaging, as a detectable flattening of the POTDR trace starting from the intrusion position. Experiments show that an intrusion leading to a 1.5 cm fiber displacement can be detected, using a 5 s averaging and 50 ns pulses with an error on the intrusion localization of the order of 5 m.

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Optical time domain reflectometer

Cited by 290 publications

References 4 publications

Coherent Noise Reduction in High Visibility Phase-Sensitive Optical Time Domain Reflectometer for Distributed Sensing of Ultrasonic Waves

Coherent Noise Reduction in High Visibility Phase-Sensitive Optical Time Domain Reflectometer for Distributed Sensing of Ultrasonic Waves

A fiber optic sensor for detecting and monitoring cracks in concrete structures

Development of an Intrusion Sensor Based on a Polarization-OTDR System

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