All-fiber Fabry-Pérot interferometer for reducing noise on the basis of differential structure

In this study, we propose a new optical fiber interferometer based on differential structure. The phase delay exists in the two output arms of the coupler. When the interference signal passes through the phase delay twice in the transmission, it produces a phase shift of π with the original signal. This feature can be used to differentially reduce noise. The experimental results show that the signal-to-noise ratio increases by 1.29 dB, and the waveform of the reconstructed signal is reduced by 12 nm. Thus, the structure can effectively improve the quality of the measured signal.