F–P interferometric cavity formed by two types of fiber Bragg gratings

We proposed and demonstrated a new type of Fabry–Perot (F–P) interferometric cavity formed by a segment of bare fiber sandwiched by a dynamic grating in an Er 3+ doped fiber and a fiber Bragg grating, in which the dynamic grating was formed in the section of Er 3+ doped fiber by the forward-propagating probe field and its reflected component because of a high reflection fiber Bragg grating at the other end. An incoherent pump was applied to amplify the modulation amplitudes of the dynamic grating and therefore to control the output spectra of the F–P interferometric cavity. The transmitted spectra of the F–P interferometric cavity have been observed with different powers of the incoherent pump, which were accordance with the theoretical analyses. The scheme has potential applications in fiber-optic communication and fiber sensors.