Application of SOI microring coupling modulation in microwave photonic phase shifters

Phase shifter is one of the key devices in microwave photonics. We report a silicon microring resonator with coupling modulation to realize microwave phase shift. With coupling tuning of the Mach-Zehnder interferometer (MZI) coupler to change the resonator from under-coupling to over-coupling, the device can realize a π phase shift on the incoming microwave signal with a frequency up to 25 GHz. The device can also realize 2.5π continuous phase tuning by manipulating the three DC bias voltages applied on the MZI coupler.