Optical characteristic measuring apparatus using interrogation optical fiber, optical fiber sensor system having the same, and optical characteristic measuring method

An optical fiber sensor system comprising:

• a light source unit which outputs an input beam of a predetermined wavelength;
• a sensing unit which receives the input beam by using a sensor, whose optical characteristic is varied according to an applied physical amount, and generates a signal beam;
• a measuring unit which derives the physical amount applied to the sensing unit by using the signal beam which is delivered from the sensing unit;
• and
• a second optical coupler which delivers the input beam, which leaves the light source unit, to the sensing unit, and distributes the signal beam, which is generated in the sensing unit, to the measuring unit,
• wherein the measuring unit includes:
• a first optical coupler which distributes the signal beam, which is delivered from the sensor, into two optical paths;
• first and second interrogation optical fibers which are arranged on respective optical paths on which the signal beam travels;
• and
• first and second detecting units which detect light intensities of a reference beam and the signal beam which have passed through the first and second interrogation optical fibers,
• wherein the first and second interrogation optical fibers are configured with optical fibers which have linear light absorption characteristics in predetermined wavelength range, light absorption slopes of the first and second interrogation optical fibers are opposite to each other, and the light intensities of the reference and the signal beams, which are detected by the detecting unit, are compared with each other to derive the physical amount applied to the sensing unit.