Photonic generation of frequency-modulated continuous-wave signal using sideband amplification injection locking effect based on the integrated mutually injected semiconductor laser

A simple photonic method to generate wideband frequency-modulated continuous-wave (FMCW) signals by taking advantage of the sideband amplification injection locking (SAIL) effect of the monolithic integrated semiconductor laser (MISL) is demonstrated in this paper. Attributing to the naturally mutual injection mechanism, when giving the MISL appropriate control currents, the MISL would enter into the undamped period-one (P1) oscillation. In this case, once one FMCW signal with appropriate power is directly modulated on the MISL with varying frequencies around the subharmonic frequency, the original P1 signal would be constantly locked by SAIL effect and stably output after the photodetector, but with different oscillating frequencies with time. Therefore, one broadband FMCW signal with several-fold central frequency and bandwidth would be realized. In this scheme, attributing to the high-integration MISL, no other additional external modulator or complex optical systems is required, highly simplifying the framework and reducing the power consumption. Furthermore, this simple and compact structure is potential to develop for photonic integration. In the experiment, one FMCW signal with varying frequencies from 16.05 GHz to 19.95 GHz is generated when the original FMCW signal ranging from 5.35 GHz to 6.65 GHz is injected, suggesting three times amplification is successfully realized. Moreover, the regenerated FMCW signal can be arbitrarily adjusted no matter in central frequency, bandwidth, pulse period or in hopping pattern as long as changing the original FMCW signal as well as the P1 frequency, showing huge flexibility and reconfigurability.