Broadband laser-tuned whispering gallery mode in a micro-structured fiber embedded with iron oxide nanoparticles

A grapefruit microstructured fiber-based resonator embedded with iron oxide nanoparticles is demonstrated in this paper. Due to efficient photon-to-heat conversion and transfer of the magnetic nanoparticles, such a device possesses broadband all-optical wavelength tuning with high sensitivity. Experimental results show that the tuning range and sensitivity can be up to ∼5.32  nm and 0.106 nm/mW, respectively, when pump laser with a wavelength of 1550 nm is injected into the resonator. Moreover, it exhibits other excellent features such as ease of fabrication and excellent repeatability, making it a good candidate for potential applications in the area of optical filtering.