The TaO-based micro-ring resonator with an unloaded quality factor of 182,000 has been demonstrated to realize efficient nonlinear wavelength generation. The propagation loss of the resonator is 0.5  cm, and the buildup factor of the ring resonator is estimated to be ∼50. With a high buildup factor of the ring structure, the four-wave-mixing (FWM) conversion efficiency of -30  dB is achieved in the resonator with a pump power of 6 mW. Based on power-dependent FWM results, the nonlinear refractive index of TaO is estimated to be 1.4×10 cm/W at a wavelength of ∼1550  nm. The demonstration of an enhanced FWM process in the TaO-based micro-ring cavity implies the possibility of realizing FWM-based optical parametric oscillation in a TaO-based micro-ring resonator.

No abstract

No abstract

Tantalum pentoxide (Ta2O5) of a large bandgap material has recently utilized to demonstrate nonlinear optical waveguide applications due to its superior linear and nonlinear optical properties [1][2], including low absorption loss coefficient in visible to infrared regions, high Kerr coefficients, and free of nonlinear absorption. In this work, the thermal-optical coefficient of tantalum pentoxide has been investigated experimentally by using a micro-ring resonator structure. Taking the advantage of index-sensitively property of ring resonator, the material with ultralow thermal-optical coefficient is easily to be measured and analyzed by using a ring waveguide structure. The cross-section of Ta2O5 based micro-ring resonator is set as 1.5μm*0.7μm, and the diameter of ring resonator is set as 100μm. By increasing the substrate temperature of micro-ring resonator, the variation of resonant wavelength of micro-ring resonator is recorded accordingly. The central wavelength of micro-ring resonator is red-shifted from 1543.430 nm to 1543.586 nm when the substrate temperature increases from 20 to 40°C. By considering the thermal-optical and thermal expansion effect of micro-ring resonator, the thermal-optical coefficient of Ta2O5 is estimated to be 6.8×10−6 / K at ~1550 nm. The thermal-optical coefficient of Ta2O5 is ten times of magnitude less than those of conventional III–V semiconductors, indicating that Ta2O5 supports the development of thermal-insensitive devices, such as sub-multiplexer and filter element.