Korea Advanced Institute of Science and Technology

Korea Research Institute of Standards and Science

Il Bum Kwon

Dong Jin Yoon

Sang Hun Kim

Jung Ju Lee

Jeong Joo Lee

San Hoon Kim

Dusun Hwang

Dong Chun Lee

The present invention is effective in that automatically corrected temperature can be measured using one light source and one optical detector.

Optic fiber distributed temperature sensor system with self-correction function and temperature measuring method using thereof

Provided is a physical quantity measuring method using a Brillouin optical fiber sensor. An optical fiber is set on a structure and a pair of pulse lights having different pulse widths is selected. The pulse lights are sequentially transmitted through the optical fiber to obtain back scattering lights and Brillouin gain spectra. The Brillouin gain spectra are compared to each other to calculate a normalized spectrum and a Brillouin frequency is acquired based on the normalized spectrum. The Brillouin frequency is multiplied by a conversion factor of a corresponding physical quantity of the structure to obtain the physical quantity. Accordingly, a portion of the optical fiber from which a sensing signal can be acquired is shortened to improve spatial resolution.

Physical quantity measuring method using Brillouin optical fiber sensor

A transmission-type extrinsic Fabry-Perot interferometric optical fiber sensor and a method used for integrity monitoring of structures and measuring strain and temperature are provided. The transmission-type extrinsic Fabry-Perot interferometric optical fiber sensor includes first single-mode optical fiber and second single-mode optical fiber, laser device, and optical detector. The first single-mode optical fiber is inserted into an end of a capillary quartz-glass tube and the second single-mode optical fiber is inserted into the other end of the capillary quartz-glass tube. Air gap is formed between the first single-mode optical fiber and the second single-mode optical fiber in the capillary quartz-glass tube. Gap length of the air gap changes in response to magnitude and direction of transformation of the capillary quartz-glass tube. The laser device launches light into an end of the first single-mode optical fiber. The end of the first single-mode optical fiber is not inserted into the capillary quartz-glass tube. The optical detector detects interferometric fringe of light. The light is launched from the laser device and passed through the first single-mode optical fiber, the air gap, and the second single-mode optical fiber. The number of occurrence of the interferometric fringe and trend of signal level are determined by change of the gap length.

Transmission-type extrinsic fabry-perot interferometric optical fiber sensor

Growing community of inventors

Daejeon, South Korea

Il Bum Kwon