A silicon photonic integrated frequency-tunable optoelectronic oscillator

A silicon photonic integrated frequency-tunable optoelectronic oscillator (OEO) is designed, fabricated and experimentally demonstrated. Three key components including a high-speed phase modulator (PM), a thermally-tunable high-Q micro-disk resonator (MDR), and a high-speed photodetector (PD) are monolithically integrated on a silicon photonic chip. The joint operation of the PM and the MDR corresponds to a microwave photonic filter (MPF) with an ultra-narrow notch that is thermally tunable. By feeding the output signal from the MPF to its input port through an electrical amplifier to provide a sufficiently large gain, the MPF becomes an OEO and oscillation starts. A microwave signal with a frequency tunale from 3 to 7 GHz is generated. The phase noise of a generated microwave signal at 5.4 GHz is measured to be -80 dBc/Hz at an offset frequency of 10 kHz.