Smart structures are to be possessed many functions to sense the external effects, such as
seismic loads, temperature, and impact by some explosion, influenced on the safety of structures.
This work was focused on the development of a sensing function of smart structures to get the
temperature distribution on structures to detect fire occurrences. A fiber optic BOTDA (Brillouin
Optical Time Domain Analysis) sensor system was developed to detect the fire occurrence by
measuring the temperature distribution of a building’s exterior surfaces. This fiber optic sensor
system was constructed with a laser diode and two electro-optic modulators, which made this
system faster than systems using only one electro-optic modulator. The temperature distributed on
an optical fiber can be measured by this fiber optic BOTDA sensor. An optical fiber, 1400 m in
length, was installed on the surface of a building. Using real-time processing of the sensor system,
we were able to monitor temperature distribution on the building’s surfaces, and changes in
temperature distribution were also measured accurately with this fiber optic sensor.
