THERMALLY TUNABLE INTEGRATED OPTICAL RING-RESONATOR WITH POLY-SI THERMISTOR

Doped polysilicon is applied as a thermo-optic heating element to temp erature tune the ring resonator based on silicon nitride db waveguides on silicon. The ring diameter is 2 mm allowing a large free spectral range of 26 GHz. For the first time, a poly-Si resistor is used as a t hermistor to measure waveguide temperature, The temperature coefficien t of the poly-Si thermistor is 9.5 x 10(-4)/degrees C, The reproducibi lity of the temperature measurement is 0.3 degrees C. The finesse of t he ring resonator is 77. The propagation loss of silicon nitride rib w aveguide is 0.5 dB/cm at the wavelength of 1.312 mu m. The temperature tuning of the ring resonator and the in situ supervision of the tempe rature on chip based ore the same poly-Si fabrication profess may find use especially in optical sensor applications.