Frequency-modulated continuous-wave laser source based on four-wave mixing process in a silicon integrated waveguide doped with reverse-biased P-i-N junction

In this paper, we propose and demonstrate a Frequency Modulated Continuous Wave (FMCW) laser source realized through sideband modulation and four-wave mixing (FWM). A silicon waveguide, featuring a reverse-biased P-i-N junction, is designed to excite FWM process. The FWM process in silicon waveguide expand threefold frequency sweeping span to 6 GHz, thereby enhancing spatial resolution to 2.5 cm. The original tuning range of 2 GHz and tuning rate of 0.2 GHz/s is multiplied by three times to 6 GHz and 0.6 GHz/μs respectively. The frequency-modulated light source exhibits excellent linearity, low noise, narrow linewidth, and fast tuning rates, which are critical attributes for modern electrical systems.