Effects of rapid thermal annealing on aluminum nitride waveguides

The effects of rapid thermal annealing (RTA) on aluminum nitride (AlN) waveguides were investigated. For the AlN prepared by the sputtering, high temperature annealing for too long time may deteriorate the device performance, while a 6-7 times RTA with a 60 s annealing at a temperature of 800 °C would result in a lowest waveguide loss of about 0.76 dB/cm. After annealing, self-pumped four-wave mixing was performed on an 800-nm-wide, 5.8-mm-long waveguide. With a pump beam launched into the waveguide, signal and idler sidebands can be generated, which shows that RTA assisted sputtering grown AlN can have a potential to be applied for optical frequency comb generation.