Low-phase-noise Dual-tone RF Signal Generation Based on an Optoelectronic Oscillator

Low-phase-noise dual-tone radio frequency (RF) signal generation is realized by injecting a low-frequency signal into a dual-passband optoelectronic oscillator (OEO). The dual-passband OEO is realized by paralleling two individual electrical filters with different center frequencies in the oscillation loop, and the injection signal’s frequency equals the frequency difference between the two generated oscillation signals. Due to the modulation nonlinearity of the oscillation loop, the low-frequency injection signal enables mutual frequency conversion between the two oscillation frequencies, leading to sustained mutual injection locking. In a proof-of-concept experiment, two RF signals with frequencies of 10.6637 GHz and 14.0008 GHz are simultaneously generated by injecting a 3.3371-GHz signal into the proposed OEO. The phase noises at a 10-kHz frequency offset of the generated RF signals are −140.06 dBc/Hz and −140.13 dBc/Hz, respectively, and the side-mode suppression ratios are larger than 60 dB.