Gallium oxide: A potentially photonic material

We fabricated Er3+/Yb3+ codoped Ga2O3 thin films via radio frequency magnetron sputtering and investigated the effect of annealing temperature and Ar/O2 gas ratio on the luminescent properties of the films. The results show that the fluorescence intensity of the film can be promoted with increasing annealing temperature, and the increase in the oxygen flow during the deposition also effectively improves the luminescent performance. The film deposited on the entire 4 in. wafer under optimal conditions exhibits a smooth surface, uniform thickness, and consistent refractive index. For the application of the films in photonic devices, we design and fabricate a microring resonator and optical amplifier. The microring resonator exhibits an intrinsic quality factor of 3.8 × 104 and a transmission loss of 2.03 dB/cm. The waveguide amplifier with a length of 2 cm possesses an internal gain of 3.8 dB at 1546 nm under a pump power of 104.71 mW from a 1480 nm laser. All these confirm that Er3+/Yb3+ codoped Ga2O3 thin films are potential to be used as the photonic material in the development of various on-chip photonic devices.