Narrow-Linewidth Photonic Microwave Generation Based on an Optically Injected Semiconductor Laser Subject to Subharmonic Modulation

We propose and experimentally demonstrate a scheme to acquire a narrow-linewidth photonic microwave based on an optically injected semiconductor laser (OISL) modulated by a subharmonic microwave from an optoelectronic oscillation (OEO). The microwave frequency generated by the OEO is 7.62 GHz, and the period-one (P1) oscillation frequency of the OISL is close to twice of it. Through modulating the OISL by a 1/2 subharmonic microwave generated by the OEO, the photonic microwave is locked at 15.24 GHz with a 3-dB linewidth about 1 kHz and a SSB phase noise of -94 dBc/Hz at offset frequency 10 kHz.