Phase-change material based external cavity laser for frequency modulated continuous wave LiDAR

We propose a novel external cavity laser (ECL) architecture incorporating an external waveguide Bragg grating (WBG) integrated with a phase-change material (PCM) layer, specifically antimony trisulfide (Sb₂S₃). Based on the substantial effective refractive index difference between the amorphous and crystalline states of Sb₂S₃, along with its fast and reversible phase-switching characteristics, the proposed design enables rapid and wide-range frequency tuning of the ECL. Simulation results indicate that a tunable frequency range of up to 100 GHz under a 1 MHz repetition rate, with an output lasing linewidth of around 41.06 kHz. This proposed ECL provides an efficient approach for frequency modulated continuous wave light detection and ranging applications, offering significant potential to enhance both resolution and ranging speed.