Continuously tunable fiber laser based on Fano resonance filter of thin-fiber-taper-coupled conical microresonator

Abstract

Through Fano resonance, the resonant modes exhibiting peak-like shapes on the bandpass spectrum of the thin-fiber-taper-coupled conical microresonator are generated. For the first time, this thin-fiber-taper-coupled conical microresonator functions as a Fano filter, and is applied as a tunable internal-cavity bandpass filter for an Erbium-doped fiber ring laser. If the size of the conical microresonator in the coupling junction is adjusted by displacing the fiber taper along the resonator axis, the wavelength of the output laser is able to be tuned linearly and continuously with a coefficient of 0.225 nm/mm.