A Frequency-Stable Optoelectronic Oscillator Based on Passive Phase Compensation

A novel passive phase compensated optoelectronic oscillator (PPC-OEO) with low frequency drift is proposed and experimentally demonstrated. It consists of a main oscillation loop and a compensation path. A passive phase compensation technique (PPCT) is adopted for the long-term frequency stabilization of the OEO. Once the optoelectronic oscillation is established, the OEO output frequency is stably locked to twice the frequency of an external signal injected into the compensation path. The experimental results show that the frequency drift of the generated radio frequency (RF) signal at 10 GHz is about 5 Hz over 6 hours. The simple structure of the proposed OEO, without any temperature control or active servo control, makes it highly reliable.