Parallel Optical Phased Array FMCW LiDAR via Frequency Division Multiplexing for High‐Speed 4D Sensing

Optical phased array (OPA)‐based frequency modulated continuous wave (FMCW) LiDAR is a promising solid‐state solution for advanced sensing. However, conventional single‐point detection LiDAR is constrained by limited point rates, while parallel detection schemes typically require balanced photodetector (BPD) arrays and subsequent acquisition circuits, leading to high hardware costs and inefficient BPD bandwidth real‐time utilization. To address these challenges, this work, to the best of our knowledge, demonstrates for the first time a parallel OPA FMCW LiDAR architecture based on frequency division multiplexing (FDM). By introducing incremental optical delays into the local reference loop, signals from multiple wavelength channels are multiplexed into distinct frequency bands, enabling simultaneous multi‐channel detection via a single BPD. In experiments covering ranging, velocimetry, and 4D imaging, we achieved 8‐channel parallel detection using a single unique bridge BPD. At a sweep repetition rate of 10 kHz, the system achieved an equivalent detection rate of 80 kHz, representing an eightfold increase in the point rate. Simultaneously, the BPD bandwidth real‐time utilization was improved eightfold compared to traditional array‐based schemes. This approach offers a scalable pathway for high‐performance OPA FMCW LiDAR.