2022 Activity Report vol.21:Tokyo University of Agriculture and Technology

Activity Report of Open Application Program 2022 vol.21 (Course B)

High−speed and high−precision Brillouin distributed optical fiber sensors for checking the safety of structures

Graduate School of Engineering, Tokyo University of Agriculture and Technology
Report from Tanaka Laboratory, Yosuke Tanaka

We hosted graduate student Intan Fatimah Sasila Binti Ghadzali and faculty member Mohd Saiful Dzulkefly Bin Zan from the National University of Malaysia for two weeks, between January 30 and February 12, 2023, and carried out a joint research program.

Our research theme is "high−speed and high−precision Brillouin distributed optical fiber sensors for checking the safety of structures." Optical fibers are optical pathways as thin as hairs used for optical communications, and this research is a foundational study to improve optical fiber functionality in systems where they are used as sensors to measure heat and distortion. Optical fibers aren't just thin, they are light and flexible, so they have no effect on a structure, even if they are embedded in or stuck to a building, tunnel, bridge, etc. If optical fibers can be incorporated into structures as sensors, it will be possible to check for abnormal distortion and temperature increases. The optical fiber sensors upon which this research is focused are referred to as "distributed," meaning they can measure temperature and distortion at arbitrary points along the optical fibers. In Malaysia and Japan, which face numerous natural disasters, these sensors are particularly applicable for the early detection of small abnormalities that could lead to disaster.

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Group photograph after the research introduction presentations

Up to now, the National University of Malaysia has particularly studied a method that enables temperature and distortion measurement along the length of the optical fibers by separating the measurement points as finely as possible. With this, they have been able to specify places where change is occurring more accurately. Meanwhile, we have been researching a method that accurately measures temperature and distortion as quickly as possible and carried out experiments to that effect. Thus, this program focused on foundational research to combine both our techniques and increase sensor performance.

After our visitors arrived in Japan, we introduced our research to each other using slides, and held a discussion about working to realize our targets. A particular gain from this was obtaining knowledge that will lead to realizing a specific system by actually running an experimental system while discussing it face−to−face.

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Discussion while running an experimental system in the laboratory
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Commemorative photograph at Shioda Laboratory, Saitama University

During their stay, Intan Fatimah Sasila Binti Ghadzali and Mohd Saiful Dzulkefly Bin Zan not only carried out experiments in the laboratory and participated in discussions, but also toured the University and visited Shioda Laboratory in Saitama University, with which we are carrying out domestic joint research, enabling them to broaden their relationships with Japanese researchers and deepen their research knowledge. The weather forecast the day before the visit to Saitama University predicted heavy snow in the afternoon, which concerned us. With the weather information in mind, we moved the visit to earlier than initially planned. Fortunately, there was no heavy snow or accompanying damage during the round−trip itinerary, and they were able to make the visit safely, tour the university, and hold discussions. As the two of them are from Malaysia, which doesn't get snow, the snow was also a good experience for them.

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Commemorative photograph at the end of the program

During their two−week stay, our visitors spoke English with the students of the laboratory, and we were able to engage in cultural exchanges between our two countries. With such a full schedule, the program's time passed in the blink of an eye. Thank you very much to the Sakura Science Program for supporting this, and to the administrative staff of our university for their help.

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At Narita Airport before returning home