A Quasi-Distributed Optical Speckle Sensor and Its Application in Pipeline Security

2008 ◽  
Author(s):  
Jun Li ◽  
Pengchao Chen ◽  
Yongjun Cai ◽  
Dongjie Tan ◽  
Hengzhang Zhou
Keyword(s):  
Experimental Test ◽  
Optical Sensor ◽  
Single Mode ◽  
Zehnder Interferometer ◽  
Multimode Interference ◽  
Underground Pipeline ◽  
Fiber Optical ◽  
Higher Sensitivity ◽  
Mach Zehnder Interferometer

A novel fiber optical speckle sensor based on multimode interference for underground pipeline intrusion detecting is investigated both theoretically and experimentally. The sensor utilizes a single mode to multimode to single mode (SMF-MMF-SMF) structure as a sensing unit, which cascade to create a quasi-distributed optical sensor. To pave it near the underground pipeline we can detect any valid intrusion caused by motion, sound or vibration acts on the fiber. Experimental test shows that the detecting distance can be about 30Km and the locating accuracy of intrusion event is ±500m. Compared with Mach-Zehnder interferometer based configuration it has a much higher sensitivity.

A Simple Optical Sensor Based on an In-line Mach-Zehnder Interferometer for Monitoring Single- and Two-phase Flows in Pipelines

2021 ◽  
pp. 1-1
Author(s):  
Victor H. R. Cardoso ◽  
Maria Thereza M. Rocco Giraldi ◽  
Cindy S. Fernandes ◽  
Marcelo O. Silva ◽  
Joao C. W. A. Costa
Keyword(s):  
Optical Sensor ◽  
Zehnder Interferometer ◽  
Two Phase Flows ◽  
Two Phase ◽  
Mach Zehnder Interferometer

scholarly journals Up-down Taper Based In-Fiber Mach-Zehnder Interferometer for Liquid Refractive Index Sensing

Sensors ◽  
2019 ◽  
Vol 19 (24) ◽  
pp. 5440 ◽  
Author(s):  
Xiaopeng Han ◽  
Chunyu Liu ◽  
Shengxu Jiang ◽  
Shuo Leng ◽  
Jiuru Yang
Keyword(s):  
Refractive Index ◽  
Temperature Fluctuation ◽  
Extinction Ratio ◽  
Single Mode ◽  
Zehnder Interferometer ◽  
Structure Parameters ◽  
Refractive Index Sensing ◽  
Polarization Maintaining Fiber ◽  
Polarization Maintaining ◽  
Mach Zehnder Interferometer

A novel in-fiber Mach-Zehnder interferometer based on cascaded up-down-taper (UDT) structure is proposed by sandwiching a piece of polarization maintaining fiber between two single-mode fibers (SMF) and by utilizing over-fusion splicing method. The dual up tapers respectively act as fiber splitter/combiner, the down taper acts as an optical attenuator. The structure parameters are analyzed and optimized. A larger interference fringe extinction ratio ~15 dB is obtained to achieve refractive index (RI) sensing based on intensity demodulation. The experimental results show that the RI sensitivity is −310.40 dB/RIU with the linearity is improved to 0.99 in the range of 1.3164–1.3444. The corresponding resolution can reach 3.22 × 10−5 RIU, which is 6.8 times higher than wavelength demodulation. The cross sensitivity which caused by temperature fluctuation is less than 1.4 × 10−4.

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