Optical fiber whispering gallery modes resonances: Applications

The properties of whispering gallery modes (WGM) resonances of an optical fiber can be exploited in a number of different applications. Making these resonances tunable is essential for many applications. Using erbiumdoped fibers to prepare the microresonator (MR), WGM resonances can be tuned by pumping the MR with an auxiliary diode laser, enabling an all-optical fine tuning of the resonances. The same idea can be exploited the other way round, an accurate measurement of pump-induced temperature variations in doped fibers can be achieved by monitoring the WGM resonances of a doped fiber when being used. In addition, a tunable narrow linewidth fiber lasers is demonstrated using a tunable MR prepared with a slightly tapered fiber.