Multiplexed Fiber Fabry–Pérot Interferometer Sensors Based on Ultrashort Bragg Gratings

This letter reports a fiber Fabry-Peacuterot interferometer sensor formed by two closely spaced ultrashort uniform Bragg gratings within fiber core. The sensor has insertion loss as low as 0.002 dB which enables a considerable increase in the sensor's multiplexing capability. Fifty sensors are experimentally multiplexed along a single fiber using a frequency-division-multiplexing method. The potential of multiplexing more than 500 sensors is theoretically expected. The sensor's application in temperature and strain measurement is also investigated