A dual-parameter fiber sensor based on few-mode fiber and fiber Bragg grating for strain and temperature sensing

An optical fiber temperature and strain fiber sensor based on the few-mode fiber (FMF) and the fiber Bragg grating (FBG) is proposed and demonstrated. The sensor unit is fabricated by a length of FMF offset splicing with one section of single-mode fiber (SMF). The temperature and strain are measured simultaneously because of the different sensitivities of the spectrum dips. The interference with the highest extinction ratio of 23 dB can be achieved. The temperature sensitivities of -34.3 pm∕°C and 10.7 pm∕°C and strain sensitivities of -2 pm∕με and 0.67 pm∕με are achieved, respectively. The proposed sensor may exhibit the great potential in fields of the dual-parameter measurement due to its compact structure, simple configuration.