Multiparameter Distributed Fiber Sensor Based on Optical Frequency-Domain Reflectometry and Bandwidth-Division Multiplexing

We demonstrate a multiparameter distributed sensing system based on optical frequency-domain reflectometry (OFDR) with a bandwidth-division multiplexing (BDM) technique. With the BDM-assisted OFDR, the sensor system can help interrogate multiple parallel sensing optical fibers by scanning the fibers within distinct spectral ranges without any cross talk. A dual-parameter distributed sensing system was set up by multiplexing two types of sensing fibers for the simultaneous independent measurement of strain and temperature. The rms deviations between the applied and measured values of the two parameters are $19~ {\mu } {\varepsilon } $ and 1.4 °C, respectively, for a sensing spatial resolution of 10 cm. The proposed multiparameter distributed sensor system offers inexpensive potential solution to continuously monitor various parameters and is effective for the health monitoring of complex distributed structures.