Fiber noise suppression for the low phase noise OEO

Radio frequency (RF) signals with extraordinary low phase noise can be produced by long-fiber optoelectronic oscillators (OEOs). These signals have wide applications, including modern communication systems, radar technology, and radio astronomy. However, the phase noise of the RF signals is primarily limited by the double-Rayleigh scattering (DRS) and the nonlinear effects in long-distance optical fibers. Based on experimental demonstration, we observe the dominated fiber noises and corresponding suppression mechanism in the open optoelectronic loop. By utilizing the methods of coherent multi-carrier and frequency modulation, a 10 GHz OEO with phase noise of -151 dBc/Hz at 10 kHz offset frequency is successfully achieved.