Microwave Generation by P2 Dynamics of Optically Injected Semiconductor Laser

In this paper, an approach for photonic generation of microwave signals by period-two (P2) dynamics in an optically injected semiconductor laser is investigated, which provides a supplementary method for generating microwave signals below the period-one (P1) oscillation frequencies. The characteristics of P2 oscillation including the frequency tunability and frequency-switching time are numerically investigated, which shows the potential of microwave signal generation by P2 dynamics. In the experiment, the generation of single-frequency and stepped-frequency (SF) microwave signals based on P2 dynamics are demonstrated. For single-frequency signal generation, optical injection combined with dual-loop optoelectronic feedback is achieved to suppress the phase noise. In the experiment, single-frequency signals with adjustable frequencies from 1.72 GHz to 8.68 GHz are generated with the phase noise lower than −118.54 dBc/Hz @10kHz and the side-mode suppression ratio (SMSR) ratio over 69.8 dB. For SF microwave signal generation, a 3-GHz (3-6 GHz) bandwidth signal with multiple discrete frequencies is generated of which the frequency stability and accuracy are improved the by incorporating single-loop optoelectronic feedback. The results validate the feasibility of microwave signal generation by P2-dyanmics, which can be applied in wireless communication and radar systems.