Simultaneous strain and temperature measurement using a superstructure fiber Bragg grating

A novel and simple fiber-optic sensor based on a superstructure fiber Bragg grating (SFBG) for simultaneous strain and temperature measurement is proposed and demonstrated. The transmission spectrum of the sensor possesses several narrow-band loss peaks situated on the slope of a broad-band loss peak. By measuring the transmitted intensity and wavelength at one of the loss peaks, strain and temperature can be determined simultaneously. The accuracy of the sensor in measuring strain and temperature is estimated to be +/-20 mu epsilon in a range from 0 to 1200 mu epsilon and +/-1.2 degrees C from 20 degrees C to 120 degrees C, respectively.