Hybrid-measurement for extrinsic F-P interferometer and fiber grating

A hybrid-measuring technology is developed in this paper to investigate extrinsic Fabry-Perot interferometric sensor and FBGs. To realize the measurements, a scanning narrow-band light is injected into EFPI or FBG, the reflected wavelength of FBG and the spectra of EFPI are calculated. The EFPI and FBGs can also be interrogated simultaneously when they are in series in one optical fiber. The results show the wavelength of FBG and the cavity length of EFPI can be measured accurately when FBG is in the front of EFPI. FBG can not be measured if it is in the front of EFPI.