Foreword

Anderson, Duwayne M.; Johnson, Larry; Bell, Florian G.

doi:10.1016/b978-012058661-5/50020-3

Cited by 2 publications

(3 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Under this point of view, we can map I-OFDR to OTDR parameters, and in fact we also use the OTDR displayed resolution, scriptW=vΔt2/2, which is the physical distance that contributes to the backscattering captured at a given instant. The factor 1/2 in W with respect to Δz accounts for the round-trip path of backscattering [39].…”

Section: Theoretical Backgroundmentioning

confidence: 99%

“…This has been the procedure followed in the present investigation. This procedure also leads to the determination of the sensitivity as the absolute noise level of the observed noise floor, computed as a rms or as a 98% value [39]. Finally, the dynamic range is defined as the difference between the highest measurable peak, typically that used for calibration, and the observed noise level in this configuration.…”

Section: Theoretical Backgroundmentioning

confidence: 99%

“…The calibration of the RBS trace is not performed through a reference reflector, but after the identification with a particular virtual probe pulse. In detail, the initial readout level |hsw(0)| is set by convention to the standard RBS coefficient σ [39] of a virtual square pulse whose width is the FWHM of the sinc pulse associated to the rectangular window [42]:|hsw(0)|≡σ=10log()SαsW=10prefixlog()SαsvΔt22 with Δt2=1.21/ηB. With this definition, the initial RBS level of traces with double bandwidth differ by 3 dB and, in turn, traces with the same bandwidth but with different windows, and therefore with different values of κ, show the same initial RBS level, but differ in resolution.…”

Section: Theoretical Backgroundmentioning

confidence: 99%

See 2 more Smart Citations

Incoherent Optical Frequency-Domain Reflectometry Based on Homodyne Electro-Optic Downconversion for Fiber-Optic Sensor Interrogation

Clement

Maestre

Torregrosa

et al. 2019

Sensors

View full text Add to dashboard Cite

Fiber-optics sensors using interrogation based on incoherent optical frequency-domain reflectometry (I-OFDR) offer benefits such as the high stability of interference in the radio-frequency (RF) domain and the high SNR due to narrowband RF detection. One of the main impairments of the technique, however, is the necessity of high-frequency detectors and vector network analyzers (VNA) in systems requiring high resolution. In this paper, we report on two C-band implementations of an I-OFDR architecture based on homodyne electro-optic downconversion enabling detection without VNA and using only low-bandwidth, high-sensitivity receivers, therefore alleviating the requirements of conventional I-OFDR approaches. The systems are based on a pair of modulators that are synchronized to perform modulation and homodyne downconversion at a reference frequency of 25.5 kHz. In the first system, we attain centimeter resolution with a sensitivity down to −90 dB using the modulation frequency range comprised between 3.2 and 14.2 GHz. In the second, we measured, for the first time using this approach, Rayleigh backscattering traces in standard single mode fiber with resolution of 6 m and a sensitivity of −83 dB by use of the 10.1–30.1 MHz range. These results show the feasibility of these simple, homodyne downconversion I-OFDR systems as compact interrogators for distributed or quasi-distributed optical fiber sensors.

show abstract

Section: Theoretical Backgroundmentioning

confidence: 99%

Section: Theoretical Backgroundmentioning

confidence: 99%

Section: Theoretical Backgroundmentioning

confidence: 99%

See 1 more Smart Citation

Incoherent Optical Frequency-Domain Reflectometry Based on Homodyne Electro-Optic Downconversion for Fiber-Optic Sensor Interrogation

Clement

Maestre

Torregrosa

et al. 2019

Sensors

View full text Add to dashboard Cite

show abstract

Secure Software for Rail Circuits in the Form of Distributed Sensors

Mgebrishvili

Явич

Iashvili

et al. 2021

Wseas Transactions on Information Science and Applications

View full text Add to dashboard Cite

In order to improve the safety of train traffic, we propose to introduce into practice a new type of rail circuits, fiber-optic rail circuits. Fiber optic cable is very sensitive to external shocks, vibration and deformation, which can play a crucial role in the detection of mechanical damage of rails and wheel sets and also to improve the positioning of the rolling stock. The branches of the fiber optic cable not only serve as a conductor of information, but also serve as a sensor, as they can perceive vibration. An OTDR (Optical Time Domain Reflectometer) analyzes the backscattered light signal to determine the shape of the physical impact that caused the bending. From the time between the emission of the light signal and the receipt of the backscattered signal, the fault location is calculated. The authors offer the model of the system, which will check the security problems of the trains and the rail circuits. The software of the corresponding system is presented, using the simulation techniques. The authors present the pseudo code of the software. They also offer the testing environment for the software.

show abstract

Foreword

Cited by 2 publications

References 0 publications

Incoherent Optical Frequency-Domain Reflectometry Based on Homodyne Electro-Optic Downconversion for Fiber-Optic Sensor Interrogation

Incoherent Optical Frequency-Domain Reflectometry Based on Homodyne Electro-Optic Downconversion for Fiber-Optic Sensor Interrogation

Secure Software for Rail Circuits in the Form of Distributed Sensors

Contact Info

Product

Resources

About