Numerical Investigation on Ultra-Broadband Tunable Microwave Frequency Comb Generation Using a Semiconductor Laser Under Regular Pulse Injection

A system scheme for generating ultra-broadband microwave frequency comb (MFC) based on a semiconductor laser under optical injection of regular pulse from a current-modulated laser is proposed, and the performances of the generated MFC are numerically investigated. In such a scheme, a distributed feedback semiconductor laser (DFB-SL1) under current modulation with suitable modulated parameters can be driven into regular pulsing state, which is utilized as a seed MFC with tunable frequency interval to inject into another distributed feedback semiconductor laser (DFB-SL2) for producing optimal MFC with ultrabroadband and tunable frequency interval. The simulated results demonstrate that for a seed MFC with a bandwidth of 26.4 GHz (27.0 GHz) and frequency interval of 3.3 GHz (2.7 GHz), the bandwidth of the optimized MFC generated by DFB-SL2 can arrive at 72.6 GHz (75.6 GHz) through selecting appropriate injection parameters.