Multipoint Temperature Sensing Using Linear-Cavity Fiber Laser with an EDFA and FBGs

Optical fiber sensors have been investigated to measure distributed distortion of large buildings, bridges and expressways. We are focusing on a fiber lasing system including sensing elements in the cavity since it has advantages such as higher resolution for wavelength shift and higher signal-to-noise ratio. A multipoint temperature sensor using linear-cavity lasing system consisting of an Erbium-doped fiber amplifier (EDFA), variable optical attenuators, and fiber Bragg grating elements is demonstrated. In order to obtain high-power and multi wavelength operation, an EDFA with appropriate power control is employed. As a result of two-point temperature measurement experiment, two-wavelength lasing and temperature-dependent wavelength change are observed. The sensitivity of 10.5 pm/deg is achieved.