scholarly journals Design of leakage monitoring system based on optical fiber side coupling effect

2022 ◽  
Vol 68 ◽  
pp. 102743
Author(s):  
Xuehua Yang ◽  
Qiao He ◽  
Yijun Li ◽  
Xiuyuan Li ◽  
Yingxue Li ◽  
...  
2017 ◽  
Vol 46 (7) ◽  
pp. 722002
Author(s):  
赵 林 Zhao Lin ◽  
王纪强 Wang Jiqiang ◽  
李 振 Li Zhen

Nano-Optics ◽  
2020 ◽  
pp. 293-304
Author(s):  
Hazli Rafis Abdul Rahim ◽  
Siddharth Thokchom ◽  
Waleed Soliman Mohammed ◽  
Joydeep Dutta ◽  
Sulaiman Wadi Harun

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2381
Author(s):  
Tianrui Zhai ◽  
Xiaojie Ma ◽  
Liang Han ◽  
Shuai Zhang ◽  
Kun Ge ◽  
...  

This article assembles a distributed feedback (DFB) cavity on the sidewalls of the optical fiber by using very simple fabrication techniques including two-beam interference lithography and dip-coating. The DFB laser structure comprises graduated gratings on the optical fiber sidewalls which are covered with a layer of colloidal quantum dots. Directional DFB lasing is observed from the fiber facet due to the coupling effect between the grating and the optical fiber. The directional lasing from the optical fiber facet exhibits a small solid divergence angle as compared to the conventional laser. It can be attributed to the two-dimensional light confinement in the fiber waveguide. An analytical approach based on the Bragg condition and the coupled-wave theory was developed to explain the characteristics of the laser device. The intensity of the output coupled laser is tuned by the coupling coefficient, which is determined by the angle between the grating vector and the fiber axis. These results afford opportunities to integrate different DFB lasers on the same optical fiber sidewall, achieving multi-wavelength self-aligned DFB lasers for a directional emission. The proposed technique may provide an alternative to integrating DFB lasers for applications in networking, optical sensing, and power delivery.


Sensor Review ◽  
2021 ◽  
Vol 41 (4) ◽  
pp. 350-360
Author(s):  
Xiao Fang ◽  
Yajie Zeng ◽  
Feng Xiong ◽  
Jiang Chen ◽  
Fei Cheng

Purpose Seepage of the dam is an important safety problem, which may cause internal erosion of the structure. In the field of seepage monitoring in civil engineering, the distributed optical fiber sensing technology based on the temperature tracing method has been paid more attention due to its unique advantages of high sensitivity, good stability and high resolution. The purpose of this paper is to make a review of the existing related research, so as to facilitate the later scholars to understand and further study more systematically. Design/methodology/approach In this paper, three kinds of commonly used distributed fiber temperature measurement technologies are introduced. Based on the working principle, monitoring system, theoretical analysis, experimental research and engineering application of the fiber seepage monitoring technology, the present situation of dam seepage monitoring based on distributed fiber is reviewed in detail and their advantages and disadvantages are compared. Findings The thermal monitoring technology of seepage measurement depends on the accuracy of optical fiber temperature measurement (including the accuracy of the system and the rationality of the discrimination method), the correct installation of optical fiber and the quantitative analysis of temperature data. The accuracy of the current monitoring system can basically meet the existing measurement requirements, but the correct installation of optical fiber and the calibration of temperature data need to be further studied for different discrimination methods, and this field has great research value. Originality/value At present, there are many applications and research studies of optical fiber sensing in the field of structural health monitoring, and there are also reviews of related aspects. However, there is little or no review only in the field of seepage monitoring. This paper summarizes the research and application of optical fiber sensing in the field of seepage monitoring. The possibility of the gradient method to find its new prospect with the development of monitoring systems and the improvement of temperature resolution is discussed. The idea of extending the seepage monitoring method based on distributed optical fiber thermal monitoring technology to other monitoring fields is also given in the paper.


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