A light-intensity-controlled microfiber-assisted Mach–Zehnder interferometer based on ethyl orange solution under 532nm laser excitation

A compact light-intensity-controlled Mach–Zehnder interferometer has been proposed by exploiting the photosensitivity of ethyl orange solution in combination with the evanescent field property of a microfiber-assisted Mach–Zehnder structure. We have experimentally investigated the influences of irradiation laser power density as well as weight percentage ratio of ethyl orange solution on the transmission spectral characteristics of the proposed microfiber-assisted fiber-optic interferometer. Experimental results indicate that the interference transmission spectra are highly sensitive to the applied excitation laser power density. An optimal ethyl orange weight percentage of 0.5 wt% has been experimentally acquired, with which the largest interference dip wavelength sensitivity reaches 0.02576 nm/(mW cm −2 ). Moreover, experimental observation on the transmission spectrum shows that the proposed MZI possesses good spectral reversibility, which ensures its applicability for practical applications.