scholarly journals A Space-Division Multiplexing Method for Fading Noise Suppression in the Φ-OTDR System

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1694
Author(s):  
Yixin Zhang ◽  
Jingxiao Liu ◽  
Fei Xiong ◽  
Xuping Zhang ◽  
Xiaohong Chen ◽  
...  
Keyword(s):  
Noise Suppression ◽  
Time Domain Reflectometry ◽  
Vibration Monitoring ◽  
Optimization Strategy ◽  
Long Distance ◽  
Space Division Multiplexing ◽  
Space Division ◽  
Phase Sensitive ◽  
Continuous Running ◽  
Distortion Rate

Phase-sensitive time-domain reflectometry (Φ-OTDR) can be used for fully distributed long-distance vibration monitoring. There is a fading phenolmenon in the Φ-OTDR, which will cause the signal intensity somewhere to be too low to extract the phase of the signal without distortion. In this paper, the Φ-OTDR based on space-division multiplexing (SDM) is proposed to suppress fading and we used multi-core optical fiber (MCF) to realize SDM. While inheriting the previous optimization strategy, we proposed a strategy based on frequency spectral similarity to process multiple independent signals obtained by SDM. And we compared the two methods. Through the experiments, the distortion rate can be reduced from an average level of 9.34% to less than 2% under continuous running of 270 s, which proves that SDM is a reliable technical route to achieve fading suppression. This method can effectively improve the fading suppression capability of the existed commercial systems.

scholarly journals Aircraft Detection Using Phase-Sensitive Optical-Fiber OTDR

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 5094
Author(s):  
Yunpeng Cai ◽  
Jihui Ma ◽  
Wenfa Yan ◽  
Wenyi Zhang ◽  
Yuhang An
Keyword(s):  
Time Domain ◽  
Random Noise ◽  
Vibration Signal ◽  
Time Domain Reflectometry ◽  
Seismic Vibration ◽  
Long Distance ◽  
Time Frequency ◽  
Phase Sensitive ◽  
The Impact ◽  
Aircraft Detection

Aircraft detection plays a vital role in aviation management and safe operation in the aviation system. Phase-Sensitive Optical Time Domain Reflectometry (Φ-OTDR) technology is a prevailing sensing method in geophysics research, structure inspection, transportation detection, etc. Compared with existing video- or radio-based detection methods, Φ-OTDR is cost-effective, suitable for long-distance detection, and resistant to severe weather conditions. We present a detection system using Φ-OTDR technology and analyze the character of the acoustic signal of aircraft. Instead of runway monitoring in the airport or noise detection in the air, this study focuses on the detection of seismic vibration signal excited by the sound of aircraft. The Chebyshev filter is adopted to eliminate the impact of background noise and random noise from the original vibration signal; the short-time Fourier transform is used for time-frequency analysis. The experimental results showed that the seismic vibration signal excited by the aircraft sound is mainly low-frequency, which is under 5 Hz. Time delay of aircraft vibration signal in different locations of the optic fiber is recorded by the sensing system. The Doppler effect is also revealed by the time-domain analysis: the frequency increases when the aircraft is approaching and decreases when the aircraft moves away.

scholarly journals Peta-bit-per-second optical communications system using a standard cladding diameter 15-mode fiber

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Georg Rademacher ◽  
Benjamin J. Puttnam ◽  
Ruben S. Luís ◽  
Tobias A. Eriksson ◽  
Nicolas K. Fontaine ◽  
...  
Keyword(s):  
Wavelength Division Multiplexing ◽  
Single Mode ◽  
Single Mode Fiber ◽  
Capacity Limits ◽  
Wavelength Division ◽  
Core Networks ◽  
Space Division Multiplexing ◽  
Space Division ◽  
Data Rates ◽  
Multi Mode

AbstractData rates in optical fiber networks have increased exponentially over the past decades and core-networks are expected to operate in the peta-bit-per-second regime by 2030. As current single-mode fiber-based transmission systems are reaching their capacity limits, space-division multiplexing has been investigated as a means to increase the per-fiber capacity. Of all space-division multiplexing fibers proposed to date, multi-mode fibers have the highest spatial channel density, as signals traveling in orthogonal fiber modes share the same fiber-core. By combining a high mode-count multi-mode fiber with wideband wavelength-division multiplexing, we report a peta-bit-per-second class transmission demonstration in multi-mode fibers. This was enabled by combining three key technologies: a wideband optical comb-based transmitter to generate highly spectral efficient 64-quadrature-amplitude modulated signals between 1528 nm and 1610 nm wavelength, a broadband mode-multiplexer, based on multi-plane light conversion, and a 15-mode multi-mode fiber with optimized transmission characteristics for wideband operation.

scholarly journals Recent Advances in Phase-Sensitive Optical Time Domain Reflectometry (Ф-OTDR)

2021 ◽  
Vol 11 (1) ◽  
pp. 1-30
Author(s):  
Yunjiang Rao ◽  
Zinan Wang ◽  
Huijuan Wu ◽  
Zengling Ran ◽  
Bing Han
Keyword(s):  
Fiber Optics ◽  
Time Domain ◽  
Acoustic Waves ◽  
Rapid Development ◽  
Development Stage ◽  
Time Domain Reflectometry ◽  
Rayleigh Backscattering ◽  
Optical Time Domain Reflectometry ◽  
Phase Sensitive ◽  
Optical Time

AbstractPhase-sensitive optical time domain reflectometry (Ф-OTDR) is an effective way to detect vibrations and acoustic waves with high sensitivity, by interrogating coherent Rayleigh backscattering light in sensing fiber. In particular, fiber-optic distributed acoustic sensing (DAS) based on the Ф-OTDR with phase demodulation has been extensively studied and widely used in intrusion detection, borehole seismic acquisition, structure health monitoring, etc., in recent years, with superior advantages such as long sensing range, fast response speed, wide sensing bandwidth, low operation cost and long service lifetime. Significant advances in research and development (R&D) of Ф-OTDR have been made since 2014. In this review, we present a historical review of Ф-OTDR and then summarize the recent progress of Ф-OTDR in the Fiber Optics Research Center (FORC) at University of Electronic Science and Technology of China (UESTC), which is the first group to carry out R&D of Ф-OTDR and invent ultra-sensitive DAS (uDAS) seismometer in China which is elected as one of the ten most significant technology advances of PetroChina in 2019. It can be seen that the Ф-OTDR/DAS technology is currently under its rapid development stage and would reach its climax in the next 5 years.

scholarly journals Monitoring of a Highly Flexible Aircraft Model Wing Using Time-Expanded Phase-Sensitive OTDR

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3766
Author(s):  
Miguel Soriano-Amat ◽  
David Fragas-Sánchez ◽  
Hugo F. Martins ◽  
David Vallespín-Fontcuberta ◽  
Javier Preciado-Garbayo ◽  
...  
Keyword(s):  
Optical Fibers ◽  
Fuel Efficiency ◽  
Optical Fiber Sensor ◽  
High Sensitivity ◽  
Time Domain Reflectometry ◽  
Structural Deformation ◽  
Flexible Wings ◽  
Sensing Technology ◽  
Distributed Optical Fiber Sensor ◽  
Phase Sensitive

In recent years, the use of highly flexible wings in aerial vehicles (e.g., aircraft or drones) has been attracting increasing interest, as they are lightweight, which can improve fuel-efficiency and distinct flight performances. Continuous wing monitoring can provide valuable information to prevent fatal failures and optimize aircraft control. In this paper, we demonstrate the capabilities of a distributed optical fiber sensor based on time-expanded phase-sensitive optical time-domain reflectometry (TE-ΦOTDR) technology for structural health monitoring of highly flexible wings, including static (i.e., bend and torsion), and dynamic (e.g., vibration) structural deformation. This distributed sensing technology provides a remarkable spatial resolution of 2 cm, with detection and processing bandwidths well under the MHz, arising as a novel, highly efficient monitoring methodology for this kind of structure. Conventional optical fibers were embedded in two highly flexible specimens that represented an aircraft wing, and different bending and twisting movements were detected and quantified with high sensitivity and minimal intrusiveness.

Multicore EDFA for space division multiplexing

2013 ◽  
Author(s):  
Yukihiro Tsuchida ◽  
Masateru Tadakuma ◽  
Ryuichi Sugizaki ◽  
Takeshi Yagi
Keyword(s):  
Space Division Multiplexing ◽  
Space Division
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