Electrical thermo-optic tuning of integrated polymethyl methacrylate sphere whispering gallery mode resonator

Tuning of an integrated polymethyl methacrylate (PMMA) sphere whispering gallery mode (WGM) resonator is demonstrated. The WGM resonator is constructed by inserting a PMMA sphere into an etched microstructured fiber with suspended core, where the sphere with diameter of 31.5μm functions as WGM cavity and suspended core with diameter of 1.5μm is used to feed and pick up WGMs. Experimental results show that the maximum quality factor of the proposed WGM resonator is 5.9×10 ⁴ and the resonant wavelength shifts toward longer wavelength as the temperature decreases. A tuning range of 1.93nm is realized by 210mA DC current due to the thermo-optic effect.