Low-loss and high-Q Ta(2)O(5) based micro-ring resonator with inverse taper structure.

Abstract

A low-loss and high-Q Ta(2)O(5) based micro-ring resonator is presented. The micro-ring resonator and channel waveguide with core area of the 700 by 400 nm(2) were fabricated on amorphous Ta(2)O(5) thin films prepared by reactive sputtering at 300°C and post annealing at 650°C for 3 hours. The Ta(2)O(5) micro-ring resonator with a diameter of 200 μm was coupled to the channel waveguide with a coupled Q up to 38,000 at a 0.9 μm coupling gap. By fitting the transmission spectrum of the resonator, the extracted loss coefficient inside the ring cavity and transmission coefficient of TE mode were 8.1dB/cm and 0.9923, leading to the estimated unloaded Q of higher than 44,000. In addition, based on the cut-back method, the propagation loss and the coupling loss of Ta(2)O(5) channel waveguide with an inverse taper were 1.5dB/cm and 3.2 dB, respectively. The proposed Ta(2)O(5) technology offers an unique alternative for fabricating high performance guided wave devices, and may well lead to novel applications in photonic integrated circuits.