GaN Photonic Integrated Circuits with High Extinction Ratio in O-band and Short-Wavelength Infrared Range

A microring resonator with an intrinsic Q-factor of ∼2.67 × 104 and an extinction ratio (ER) of 35.1 dB at 1320 nm, is monolithically integrated with grating couplers and a ridge waveguide on a GaN-on-sapphire platform. By further designing apodized grating couplers, working wavelength of our GaN PIC extends to near infrared wavelength (~2.1 um).