Bias drift free optoelectronic oscillator based on a Sagnac loop

In this paper, we proposed and experimentally demonstrated a novel bias drift free optoelectronic oscillator (OEO) based on Sagnac loop. In the experiment, we built a Sagnac loop as the modulator of OEO where a phase modulator was used to introduce non-reciprocity without bias drift problem. 10 GHz microwave signals with relatively pure spectrum were generated and the measured phase noise was -82dBc/Hz at 10 kHz offset frequency. As a result, the feasibility of the proposed OEO is verified.