Fig. 1. Schematic diagram of the optoelectronic oscillator of optically-injected-based semiconductor laser

Fig. 2. Principle of optically injected semiconductor laser

Fig. 3. Principle of subharmonic microwave modulation

Fig. 4. Measured 15.34 GHz signal spectrum without subharmonic microwave modulation OEO with a span of 2 GHz

Fig. 5. Frequency drifted 15.31 GHz microwave signal without subharmonic microwave modulation OEO with a span of 1 GHz

Fig. 6. Generated microwave signal spectrum of OEO at different frequencies

Fig. 7. Measured 15 GHz signal spectrum of the open-loop structure with a span of 2 MHz

Fig. 8. Measured 15 GHz signal spectrum of the OEO loop with a span of 2 MHz

Fig. 9. Measured 15 GHz signal spectrum of the OEO loop with a span of 10 MHz

Fig. 10. Measured phase noise of the generated 15 GHz microwave signals