Phase Noise Suppression in a Sagnac Loop Optoelectronic Oscillator

A Sagnac loop OEO incorporating a phase noise detection and control servo is proposed and experimentally demonstrated in this paper. In the Sagnac loop within the OEO, a phase modulator and a π/2 nonreciprocal phase shifter (NRPS) are utilized. Therefore, the OEO needs no additional bias control to maintain stabilized operation. Besides, the phase noise detection and control servo could significantly suppress the phase noise. The experimental verification demonstrates that the phase noise performance could be improved by 10 dB.