Microwave signal generation from a parity-time-symmetric optoelectronic oscillator with optical injection locking

作者：Jiao, Z. H. E. J. I. N. G.^*; Zuo, P. E. N. G. C. H. E. N. G.; Xue, L. I. A. N. G.; LI, G. A. O. F. A. N. G.; Chen, Y. A. N. G.

来源：APPLIED OPTICS, 2022, 61(33): 9868-9872.

DOI：10.1364/AO.475738

• LOW PHASE NOISE

A parity-time (PT) symmetric optoelectronic oscillator (OEO) with optical injection locking is proposed and experimentally demonstrated to generate single-mode microwave signals. A distributed feedback laser is injection locked, which functions as a frequency multiplier for the coarse mode selection of the PT-symmetric OEO. The PT symmetry in the OEO is implemented by using a polarization-dependent Sagnac loop to form two identical loops for coupling. By tuning the two polarization controllers in the Sagnac loop, the gain/loss and coupling coefficient of the two loops can be controlled, and single-mode oscillation in the OEO could be achieved at the broken PT -symmetry condition. Microwave signal generation at the frequency of 6.427 GHz is obtained from the proposed OEO. The phase noise is about -105 dBc/Hz at an offset frequency of 10 kHz.